7th Grade - CHpater 4 ONLINE REVEIW
Modified True/False
Indicate whether the statement is true or false. If false, change the identified word or phrase to make the statement true.
____ 1. To locate a mall close to you, you need to know it's distance. _________________________
____ 2. The speed you read on your speedometer is the constant speed. _________________________
____ 3. When you ride your bike around a corner at 10 m/s, you are accelerating. _________________________
____ 4. To determine if an object has changed position, you need to know it's position relative to another object. _________________________
____ 5. Acceleration is caused by any forces. _________________________
____ 6. An example of a contact force is magnetism. _________________________
____ 7. You push on a book and it moves. The forces acting on it must be action-reaction forces. _________________________
____ 8. If an unbalanced force is acting on a rope, the rope will accelerate in the direction of the unbalanced force. _________________________
____ 9. If an astronaut were to land on Jupiter, his mass would increase. _________________________
____ 10. An insect falls from a twenty-story building and walks away when he hits the sidewalk because of contact forces. _________________________
____ 11. Sliding friction keeps you in the seat when a car goes around a corner. _________________________
____ 12. Forces always occur alone. _________________________
____ 13. If you throw a ball into the air, Earth exerts a force on the ball. The ball in the air exerts no force. _________________________
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____ 14. Electric, magnetic, and gravitational forces are all examples of which type of force?
a.
balanced
b.
contact
c.
non-contact
d.
unbalanced
____ 15. Which of the following has a net force of zero?
a.
balanced force
b.
buoyant force
c.
gravitational force
d.
unbalanced force
____ 16. Max is pushing a book across a table. When he stops pushing, the book slows down and stops. This is an example of which force?
a.
air resistance
b.
buoyancy
c.
gravity
d.
sliding friction
____ 17. When does a gravitational force between two objects increase?
a.
when the mass of the objects increases
b.
when the speed of the objects increases
c.
when the mass of the objects decreases
d.
when the speed of the objects decreases
____ 18. An object at rest remains at rest. An object in motion keeps moving in a straight line at a constant speed. Which of Newton’s laws of motion does this describe?
a.
first law
b.
second law
c.
third law
d.
first and third laws together
____ 19. Mark is traveling 3 mi north at 2 mph. Which of the following can be figured out with this information?
a.
acceleration
b.
average speed
c.
displacement
d.
velocity
____ 20. Susan made a diagram to show how the relationship between a buoyant force and gravity.
Which answer BEST describes the relationship shown in the diagram?
a.
Buoyancy and gravity together balance an object.
b.
Buoyant forces move at a faster rate than gravity.
c.
Gravity is more powerful than buoyancy.
d.
Objects do not know whether they will be pulled up or down
____ 21. Which law of motion says that the ground pushes back on you when you push down on it?
a.
first law
b.
second law
c.
third law
d.
fourth law
____ 22. The Average Speed equation states that average speed in meters per second equals distance in meters divided by time in seconds. If Jan travels 63 m in 7 s, what is her average speed?
a.
7 m/s
b.
9 m/s
c.
14 m/s
d.
63 m/s
____ 23. When is an object NOT accelerating?
a.
when it changes speed
b.
when it changes direction
c.
when it changes force
d.
when it changes velocity
____ 24. Donna measured the displacement and time for a traveling object.
What is the velocity of the object?
a.
2 km/h south
b.
3 km/h south
c.
4 km/h south
d.
6 km/h south
____ 25. According to Newton’s second law of motion, how is acceleration related to net force?
a.
When net force on an object increases, acceleration increases.
b.
When net force on an object decreases, acceleration increases.
c.
When acceleration changes, net force stays the same.
d.
When net force changes, acceleration stays the same.
____ 26. Which statement best describes Newton’s third law of motion?
a.
All forces are equal.
b.
An object at rest tends to stay at rest.
c.
Forces always act in pairs.
d.
Some forces have no reaction.
____ 27. Motion is change in ____.
a.
speed
c.
force
b.
velocity
d.
position
____ 28. ____ is rate of change of position.
a.
Speed
c.
Acceleration
b.
Velocity
d.
Displacement
____ 29. You travel 200 km in 2 h. Your ____ speed is 100 km/h.
a.
constant
c.
instantaneous
b.
average
d.
initial
____ 30. When a car slows down at a traffic light, it is ____.
a.
accelerating
c.
decreasing its displacement
b.
traveling at constant velocity
d.
changing direction
____ 31. You hear that a storm is moving 15 km/h north. You have been given the storm's ____.
a.
constant speed
c.
velocity
b.
acceleration
d.
average speed
____ 32. Inertia is a measure of the ____ of an object.
a.
weight
c.
constant speed
b.
mass
d.
acceleration
____ 33. The unit of force is ____.
a.
m/s
c.
the joule
b.
the hertz
d.
the newton
____ 34. When two birds are pulling on a worm and the worm moves toward the first bird, you know that the forces are ____.
a.
long-range
c.
unbalanced
b.
action-reaction
d.
balanced
____ 35. An unbalanced force acting on an object causes it to ____.
a.
move at constant speed
c.
not change its velocity
b.
continue in a straight line
d.
accelerate
____ 36. A planet is discovered that is the same size as Earth and has the same gravitational acceleration, but has twice the mass. If you weigh 700 N on Earth, on the new planet you would weigh ____.
a.
350 N
c.
1,400 N
b.
700 N
d.
2,800 N
____ 37. The force that opposes motion is ____.
a.
a balanced force
c.
an accelerating force
b.
an unbalanced force
d.
friction
____ 38. Every force has a(n) ____ force.
a.
reaction
c.
opposite
b.
long-range
d.
accelerating
____ 39. You throw a ball into the air. As the ball leaves your hand, the force(s) acting on it is/are ____.
a.
gravity
c.
balanced
b.
your hand
d.
gravity and your hand
Completion
Complete each statement.
40. If you walk one mile to a store and one mile back, your distance is ____________________ and your displacement is ____________________.
41. If you ride your bike 2 miles on a straight road between Gooseberry Junction and Happy Valley, your distance is ____________________ and your displacement is ____________________.
42. ____________________ is the change in velocity divided by the change in time.
43. Speeding up, slowing down, and going around curves are examples of ____________________.
44. If you are riding on a skateboard and it stops suddenly, your body keeps moving forward. This is because of ____________________.
45. A(n) ____________________ is a push or a pull.
46. Forces that change an object's motion by touching the object are ____________________ forces.
47. A spacecraft orbits the Earth at a constant speed. The forces acting on it must be ____________________.
48. Acceleration due to gravity at the Earth's surface is ____________________.
49. A car going around a corner, hits an icy path, and skids off the road. This represents a change from rolling friction to ____________________ friction.
50. Wagons have wheels instead of runners because ____________________ friction is less than ____________________ friction.
51. When you catch a ball, the ball creates force on your hand. The reaction force is ____________________.
52. If you throw a ball into the air, at the top of the path the force(s) acting on the ball is/are ____________________.
Choose the term or phrase that best completes each sentence.
53. If you drive from New York to San Francisco by way of Mt. Rushmore, Yellowstone National Park, and Branson, Missouri, your distance traveled is ____________________ (greater than, less than, the same as) your displacement.
54. When your feet push on the floor so that you can walk across the room, you move but the floor doesn’t. The force of the floor on your feet is ____________________ (greater than, less than, the same as) the force of your feet on the floor.
55. Standing still in a windstorm is an example of ____________________ (static, sliding, rolling) friction between your feet and the ground.
56. To push a box across the floor takes more force than to push the same box on wheels across the floor. This shows that rolling friction is ____________________ (greater than, less than, equal to) sliding friction.
57. In order to keep a race car going around a circular track at constant speed, ____________________ (no force, a balanced force, an unbalanced force) is needed.
58. A reaction force is created ____________________ (before, after, at the same time as) its action force.
59. The force needed to accelerate a full-size car to a given velocity is ____________________ (greater than, less than, equal to) the force needed to accelerate a motorcycle to the same velocity.
60. The displacement of a car driving a winding road up a mountain is ____________________ (greater than, less than, the same as) the distance the car travels.
61. When you push off of the side of a swimming pool, the force of your foot on the wall is created ____________________ (before, after, at the same time as) the force of the wall on your foot.
62. When a ball starts to fall through the air, the force of air resistance on the ball is ____________________ (greater than, less than, the same as) the force of gravity.
63. The mass of an astronaut ____________________ (increases, decreases, remains the same) when the astronaut goes on a space walk.
64. A crumpled piece of paper falls to the ground faster than a smooth piece because of ____________________.
65. When you push a book across your desk, the force of your hand is ____________________ the force of static friction.
66. The force needed to accelerate a bowling ball to a given velocity is ____________________ the force needed to accelerate a soccer ball to the same velocity.
67. A radio-controlled plane flies 75 m north, then 95 m south. Its ____________________ is 20 m south.
68. A car that travels 200 km in 2 h has a(n) ____________________ speed of 100 km/h.
69. ____________________ keeps you from sliding backward when you climb a hill.
70. ____________________ is the tendency of a body to resist change in its motion.
71. Forces always occur in equal but opposite ____________________.
Matching
Match each item with the correct description below.
a.
static friction
k.
Unbalanced forces
b.
force
l.
Acceleration
c.
rolling friction
m.
Inertia
d.
displacement
n.
Speed
e.
first law of motion
o.
Second law of motion
f.
Newton’s laws of motion
p.
Friction
g.
Sliding friction
q.
Air resistance
h.
Velocity
r.
Mass
i.
Balanced forces
s.
Newton (N)
j.
Third law of motion
t.
weight
____ 72. the distance and direction between starting and ending positions
____ 73. the distance traveled divided by the time needed to travel the distance
____ 74. change in velocity divided by the amount of time required for the change to occur
____ 75. displacement divided by time
____ 76. an object will remain at rest or move in a straight line with constant speed unless it is acted upon by a force
____ 77. equal forces that move in opposite directions
____ 78. a push or a pull
____ 79. forces that move in opposite directions that are not of equal strength
____ 80. a force that resists motion
____ 81. an object acted upon by an unbalanced force will accelerate in the direction of the force
____ 82. forces always act in equal but opposite pairs
____ 83. Air molecules act on the forward-moving surface of an object, slowing its motion.
____ 84. The type of friction that makes a tire turn and a ball roll is called ____.
____ 85. the friction that occurs when two surfaces slide past each other
____ 86. the friction that hinders a stationary object from moving on a surface when a force is applied to that object
____ 87. a force that can change when acceleration due to gravity changes
____ 88. a measure of the amount of matter in an object
____ 89. measures an object’s tendency to remain at rest or keep moving with constant velocity
____ 90. used to measure force
____ 91. a set of rules used to predict and explain motion
Match Newton’s laws of motion with the examples given.
a.
Newton’s first law
c.
Newton’s third law
b.
Newton’s second law
____ 92. A magician pulls the table cloth off a table, leaving the dishes on the table.
____ 93. A ball rolling across the floor eventually comes to a stop.
____ 94. A rower’s arms push the oars against the water. The boat moves forward after the water pushes against the oars.
____ 95. A rock moves slower when shot out of a slingshot than a pebble shot out of the same slingshot.
____ 96. You jump off a raft in the swimming pool, and when you turn around to get back on the raft, the raft has floated off in the opposite direction.
Match the unit with the quantity it measures.
a.
second
d.
m/s2
b.
newton
e.
meter
c.
m/s
____ 97. speed
____ 98. distance
____ 99. force
____ 100. time
____ 101. acceleration
Short Answer
102.
Explain the difference between speed and velocity.
103.
Mr. French’s class is using a toy car to study Newton’s laws of motion.
Part A What does Newton’s first law state?
Part B Give an example of how the class can use the toy car to demonstrate how the law works.
104.
Compare and contrast distance and displacement.
105.
Compare and contrast speed and velocity.
106.
If you run three laps around a circular race track at 5 m/s, what do you know about your speed, velocity, and acceleration?
107.
Is it necessary for an object to be in motion if it has forces acting on it? Why or why not?
108.
"If no forces are acting on a moving object, it will eventually come to rest." Comment on this statement.
109.
If you were playing football on the space station, would it be as hard to stop a 150-kg lineman as it would be on Earth? Why or why not?
110.
How is force similar to displacement and velocity?
111.
You drop a pebble from a bridge and it goes faster and faster before it hits the water. What do you know about the forces acting on the pebble?
112.
If a body is in motion at constant speed in a straight line, what, if any, forces could be acting on it?
113.
How could you decrease the force a horse needed to pull a wagonload of hay?
114.
For a long time, all experiments showed that a force had to be applied to keep a body in motion at constant velocity. How does our knowledge of the force of friction help us to understand, now, that this isn't true?
Figure 23-1
115.
In Figure 23-1, identify two pairs of action-reaction forces involving the rope.
116.
In Figure 23-1, identify two balanced forces involving the rope.
117.
In Figure 23-1, if the black dog starts pulling on the rope harder than the white dog, what will happen to the rope?
118.
In Figure 23-1, how could the rope-on-black-dog force be increased?
119.
In Figure 23-1, if the rope moves toward the white dog, what do you know about the forces on the rope?
120.
If you throw a ball into the air, after it leaves your hand, what is/are the net force(s) acting on it? Describe the ball's acceleration.
121. A high speed train travels south for 2.00 h for a distance of 454 km. What is its average velocity?
122. A coasting car slows down from 27 m/s to 24 m/s in 6 s. What is the car’s acceleration?
123. Calculate the force necessary to accelerate a 0.14-kg hardball at a rate of 100 m/s2.
124. A car travels 528 km in six hours. Find its average speed.
125. The maximum acceleration of a fist in a karate punch is 3800 m/s2. The mass of the fist is 0.70 kg. If the fist hits a wooden block, what force does the wood place on the fist?
126. When a ball is dropped it is easy to see that Earth exerts a force on it. Why can’t you tell that the ball exerts a force on Earth?
127. If you and your friend ride bumper cars at the fair, what happens, in terms of Newton’s third law, when they collide?
128. If you bump into a heavy desk sitting on a carpet, it doesn’t move. Explain.
129. Is it possible to have a single force? Explain why or why not.
130. It has been found that when a karate blow of a fist strikes a wooden block, the block can exert a force of 2,450 N on the hand. What force must be put on the block to break it?
Problem
131.
0.30 s after seeing a puff of smoke rise from the starter's pistol, the sound of the firing of the pistol is heard by the track timer 100 m away. What is the speed of sound?
132.
A top-fuel dragster accelerates from rest to a velocity of 100 m/s in 8 s. What is the acceleration?
133.
On Planet Zorg, a 30-kg barbell can be lifted by only exerting a force of 180 N. What is the acceleration of gravity on Planet Zorg?
134.
A racing car has a mass of 750 kg. It undergoes an acceleration of 4.00 m/s2. What is the net force acting on the car?
Essay
135. An astronaut in the space shuttle turns a screwdriver clockwise. The astronaut starts to rotate in a counterclockwise direction. Why does this happen?
136. You are worried about a severe storm in your area. You hear a weather broadcast that says that the storm is moving at a speed of 25 km/h. Is this all you need to know for safety? Explain why or why not in terms of speed and velocity.
137. You ride three full turns around on a merry-go-round horse. What is your displacement? Your speed is constant; is your velocity constant? Why or why not?
138. A dog on a chain is fastened to the side of a house.
a. As the dog pulls on the end of the chain, name two pairs of action-reaction forces acting on the chain.
b. What are the balanced forces on the chain?
c. What happens to the forces on the chain if the dog pulls the chain away from the wall and runs to play?
7th Grade - CHpater 4 ONLINE REVEIW
Answer Section
MODIFIED TRUE/FALSE
1. ANS: F, displacement
PTS: 1 DIF: Webb's I OBJ: 1/1 STA: SC.C.1.3.1
2. ANS: F, instantaneous
PTS: 1 DIF: Webb's I OBJ: 2/1 STA: SC.C.1.3.1
3. ANS: T PTS: 1 DIF: Webb's I
OBJ: 2/1 STA: SC.C.1.3.1
4. ANS: T PTS: 1 DIF: Webb's I
OBJ: 1/1 STA: SC.C.1.3.1
5. ANS: F, unbalanced
PTS: 1 DIF: Webb's I OBJ: 6/2 STA: SC.C.1.3.1
6. ANS: F, long-range
PTS: 1 DIF: Webb's I OBJ: 4/2 STA: SC.C.2.3.1 SC.C.2.3.2
7. ANS: F, unbalanced
PTS: 1 DIF: Webb's I OBJ: 6/2 STA: SC.C.2.3.2 SC.C.2.3.6
8. ANS: T PTS: 1 DIF: Webb's I
OBJ: 6/2 STA: SC.C.2.3.6
9. ANS: F, remain the same
PTS: 1 DIF: Webb's I OBJ: 7/3
10. ANS: F, air resistance
PTS: 1 DIF: Webb's I OBJ: 8/3 STA: SC.C.2.3.2
11. ANS: F, Static
PTS: 1 DIF: Webb's I OBJ: 8/3 STA: SC.C.2.3.2
12. ANS: F, in pairs
PTS: 1 DIF: Webb's I OBJ: 10/4 STA: SC.C.2.3.2 SC.C.2.3.6
13. ANS: F, a force on Earth
PTS: 1 DIF: Webb's I OBJ: 11/4 STA: SC.C.2.3.1
MULTIPLE CHOICE
14. ANS: C PTS: 1 DIF: Webb's I STA: SC.C.2.3.1
15. ANS: A PTS: 1 DIF: Webb's I STA: SC.C.2.3.3
16. ANS: D PTS: 1 DIF: Webb's II STA: SC.C.2.3.2 SC.C.2.3.3
17. ANS: A PTS: 1 DIF: Webb's II STA: SC.C.2.3.7
18. ANS: A PTS: 1 DIF: Webb's I STA: SC.C.2.3.5
19. ANS: D PTS: 1 DIF: Webb's I STA: SC.C.1.3.1
20. ANS: C PTS: 1 DIF: Webb's II STA: SC.C.2.3.1
21. ANS: C PTS: 1 DIF: Webb's II STA: SC.C.2.3.3
22. ANS: B PTS: 1 DIF: Webb's II STA: SC.C.1.3.1
23. ANS: C PTS: 1 DIF: Webb's I STA: SC.C.1.3.1
24. ANS: B PTS: 1 DIF: Webb's II STA: SC.C.1.3.1
25. ANS: A PTS: 1 DIF: Webb's II STA: SC.C.2.3.6
26. ANS: C PTS: 1 DIF: Webb's II STA: SC.C.2.3.3
27. ANS: D PTS: 1 DIF: Webb's I OBJ: 1/1
STA: SC.C.1.3.1
28. ANS: A PTS: 1 DIF: Webb's I OBJ: 2/1
STA: SC.C.1.3.1
29. ANS: B PTS: 1 DIF: Webb's I OBJ: 3/1
STA: SC.C.1.3.1
30. ANS: A PTS: 1 DIF: Webb's I OBJ: 2/1
STA: SC.C.1.3.1 SC.C.2.3.3 SC.C.2.3.5
31. ANS: C PTS: 1 DIF: Webb's I OBJ: 2/1
STA: SC.C.1.3.1
32. ANS: B PTS: 1 DIF: Webb's I OBJ: 5/2
33. ANS: D PTS: 1 DIF: Webb's I OBJ: 4/2
34. ANS: C PTS: 1 DIF: Webb's I OBJ: 6/2
STA: SC.C.2.3.2
35. ANS: D PTS: 1 DIF: Webb's I OBJ: 10/4
STA: SC.C.2.3.2
36. ANS: C PTS: 1 DIF: Webb's I OBJ: 7/3
STA: SC.A.1.3.2 SC.C.2.3.1
37. ANS: D PTS: 1 DIF: Webb's I OBJ: 8/3
STA: SC.C.2.3.2 SC.C.2.3.5
38. ANS: C PTS: 1 DIF: Webb's I OBJ: 10/4
STA: SC.C.2.3.3
39. ANS: D PTS: 1 DIF: Webb's I OBJ: 10/4
STA: SC.C.2.3.1
COMPLETION
40. ANS: 2 miles, 0
PTS: 1 DIF: Webb's II OBJ: 1/1 STA: SC.C.1.3.1
41. ANS: 2 miles, 2 miles
PTS: 1 DIF: Webb's II OBJ: 1/1 STA: SC.C.1.3.1
42. ANS: Acceleration
PTS: 1 DIF: Webb's I OBJ: 2/1 STA: SC.C.1.3.1
43. ANS: acceleration
PTS: 1 DIF: Webb's I OBJ: 2/1 STA: SC.C.1.3.1
44. ANS: inertia
PTS: 1 DIF: Webb's I OBJ: 5/2 STA: SC.C.2.3.6
45. ANS: force
PTS: 1 DIF: Webb's I OBJ: 4/2 STA: SC.C.2.3.1 SC.C.2.3.2
46. ANS: contact
PTS: 1 DIF: Webb's I OBJ: 4/2 STA: SC.C.2.3.2
47. ANS: balanced
PTS: 1 DIF: Webb's I OBJ: 6/2 STA: SC.C.2.3.1 SC.C.2.3.6
48. ANS: 9.8m/sec2
PTS: 1 DIF: Webb's I OBJ: 7/3 STA: SC.C.2.3.1
49. ANS: sliding
PTS: 1 DIF: Webb's I OBJ: 8/3 STA: SC.C.2.3.5
50. ANS: rolling, sliding
PTS: 1 DIF: Webb's II OBJ: 8/3 STA: SC.C.2.3.2
51. ANS: hand-on-ball
PTS: 1 DIF: Webb's II OBJ: 10/4 STA: SC.C.2.3.2
52. ANS: gravity, air resistance
PTS: 1 DIF: Webb's II OBJ: 10/4 STA: SC.C.2.3.2 SC.C.2.3.3
53. ANS: greater than
PTS: 1
54. ANS: the same as
PTS: 1
55. ANS: static
PTS: 1
56. ANS: less than
PTS: 1
57. ANS: an unbalanced force
PTS: 1
58. ANS: at the same time as
PTS: 1
59. ANS: greater than
PTS: 1
60. ANS: less than
PTS: 1
61. ANS: at the same time as
PTS: 1
62. ANS: less than
PTS: 1
63. ANS: remains the same
PTS: 1
64. ANS: air resistance
PTS: 1
65. ANS: greater than
PTS: 1
66. ANS: less than
PTS: 1
67. ANS: displacement
PTS: 1
68. ANS: average
PTS: 1
69. ANS: friction
PTS: 1
70. ANS: inertia
PTS: 1
71. ANS: pairs
PTS: 1
MATCHING
72. ANS: D PTS: 1
73. ANS: N PTS: 1
74. ANS: L PTS: 1
75. ANS: H PTS: 1
76. ANS: E PTS: 1
77. ANS: I PTS: 1
78. ANS: B PTS: 1
79. ANS: K PTS: 1
80. ANS: P PTS: 1
81. ANS: O PTS: 1
82. ANS: J PTS: 1
83. ANS: Q PTS: 1
84. ANS: C PTS: 1
85. ANS: G PTS: 1
86. ANS: A PTS: 1
87. ANS: T PTS: 1
88. ANS: R PTS: 1
89. ANS: M PTS: 1
90. ANS: S PTS: 1
91. ANS: F PTS: 1
92. ANS: A PTS: 1
93. ANS: A PTS: 1
94. ANS: C PTS: 1
95. ANS: B PTS: 1
96. ANS: C PTS: 1
97. ANS: C PTS: 1
98. ANS: E PTS: 1
99. ANS: B PTS: 1
100. ANS: A PTS: 1
101. ANS: D PTS: 1
SHORT ANSWER
102. ANS:
Speed is defined as the distance traveled divided by the time needed to travel that distance. It is a change in position over time. Velocity takes direction into account as well as distance and time. Velocity is the distance traveled in a certain direction divided by the time it takes to travel that distance.
PTS: 1 DIF: Webb's II STA: SC.C.1.3.1
103. ANS:
Part A Newton’s first law of motion states that forces acting on an object are balanced. An object at rest tends to stay at rest and an object in motion keeps moving in a straight line with a constant speed. The net force on the object remains the same.
Part B The class can demonstrate the law by observing the car at rest and then applying a force to make the car move. However, the net force on the object will change directions because of friction acting on the car. The car will eventually slow down and stop.
PTS: 1 DIF: Webb's III STA: SC.C.2.3.5
104. ANS:
They both involve a distance, but displacement also involves a direction.
PTS: 1 DIF: Webb's II OBJ: 1/1 STA: SC.C.1.3.1
105. ANS:
Both quantities measure speed, but velocity includes direction by calculating displacement.
PTS: 1 DIF: Webb's II OBJ: 2/1 STA: SC.C.1.3.1
106. ANS:
Your speed is constant. Your velocity is changing because you are changing direction. And, you are constantly accelerating because your velocity is changing.
PTS: 1 DIF: Webb's II OBJ: 2/1 STA: SC.C.1.3.1
107. ANS:
No, it is not necessary. The forces can be balanced and acting on an object that is at rest.
PTS: 1 DIF: Webb's II OBJ: 6/2 STA: SC.C.1.3.1 SC.C.2.3.3
108. ANS:
It is not true. If no forces act on a moving object, it will continue at constant velocity. It takes an unbalanced force to stop an object in motion.
PTS: 1 DIF: Webb's II OBJ: 5/2 STA: SC.C.2.3.5
109. ANS:
It would be just as hard because mass, and therefore inertia, does not change.
PTS: 1 DIF: Webb's II OBJ: 5/2 STA: SC.C.2.3.1 SC.C.2.3.2
110. ANS:
They all require a number (amount) and a direction.
PTS: 1 DIF: Webb's II OBJ: 6/2
111. ANS:
They are unbalanced. There is an unbalanced force causing acceleration.
PTS: 1 DIF: Webb's II OBJ: 6/2 STA: SC.C.1.3.1 SC.C.2.3.3
112. ANS:
There could be balanced forces acting on it.
PTS: 1 DIF: Webb's II OBJ: 6/2 STA: SC.C.1.3.1 SC.C.2.3.3 SC.C.2.3.5
113. ANS:
Possible answers: remove some of the hay from the wagon, reduce the rolling friction of the wheels.
PTS: 1 DIF: Webb's II OBJ: 10/4 STA: SC.C.2.3.3 SC.C.2.3.2
114. ANS:
The force of friction acts in opposition to motion. Therefore it is the force of friction which must be balanced in order to keep an object in motion in a constant velocity. Without friction, an object in motion at constant velocity would remain so unless acted upon by an unbalanced force.
PTS: 1 DIF: Webb's II OBJ: 10/4 STA: SC.C.2.3.5 SC.H.1.3.1
115. ANS:
black dog on rope; rope on black dog; white dog on rope; rope on white dog
PTS: 1 DIF: Webb's II OBJ: 10/4 STA: SC.C.2.3.2 SC.C.2.3.3
116. ANS:
white dog on rope; black dog on rope
PTS: 1 DIF: Webb's II OBJ: 9/3 STA: SC.C.2.3.3
117. ANS:
The rope will move in the direction of the black dog.
PTS: 1 DIF: Webb's II OBJ: 6/2 STA: SC.C.2.3.3
118. ANS:
If the black dog pulled harder on the rope.
PTS: 1 DIF: Webb's II OBJ: 6/2 STA: SC.C.2.3.3
119. ANS:
The forces on the rope are unbalanced. The white-dog-on-rope force is greater than the black-dog-on-rope force.
PTS: 1 DIF: Webb's II OBJ: 6/2 STA: SC.C.2.3.3
120. ANS:
The forces acting on the ball are hand-on-ball, gravity, and air resistance. After it leaves your hand, first it accelerates upward, then slows down, stops, and starts speeding up downward.
PTS: 1 DIF: Webb's II OBJ: 10/4 STA: SC.C.2.3.6
121. ANS:
v = d/t = 454 km/2.00 h = 227 km/h south
PTS: 1
122. ANS:
a = vf – vit = (24 m/s – 27 m/s)/6 s = –0.5 m/s2
PTS: 1
123. ANS:
F = ma = 0.14 kg ´ 100 m/s2 = 14 N
PTS: 1
124. ANS:
v = d/t = 528/6 h = 88 km/h
PTS: 1
125. ANS:
F = ma = 0.70 kg ´ 3,500 m/s2 = 2,450 N
PTS: 1
126. ANS:
Earth is so massive that the ball doesn’t accelerate it noticeably.
PTS: 1
127. ANS:
When the cars collide, each car exerts a equal but opposite force on the other car. The cars move apart in opposite directions.
PTS: 1
128. ANS:
Static friction between the desk and the carpet keeps the desk from moving.
PTS: 1
129. ANS:
It is not possible. For every action force there is a reaction force.
PTS: 1
130. ANS:
anything over 2,450 N
PTS: 1
PROBLEM
131. ANS:
s = d/t = 100 m/0.30s = 333 m/s
PTS: 1 DIF: Webb's II OBJ: 3/1 STA: SC.C.1.3.1 SC.C.1.3.2
132. ANS:
a = (vf – vl)/t = (100m/s – 0)/8 s = 12.5 m/s2
PTS: 1 DIF: Webb's II OBJ: 3/1 STA: SC.C.1.3.1
133. ANS:
a = F/m = 189 N/30 kg = 6.0 m/s2
PTS: 1 DIF: Webb's II OBJ: 7/3 STA: SC.C.2.3.7
134. ANS:
F = ma = 750 kg (4.00 m/s2) = 3,000 N
PTS: 1 DIF: Webb's II OBJ: 7/3 STA: SC.C.2.3.6
ESSAY
135. ANS:
When the astronaut exerts a clockwise force on the screwdriver, the screwdriver exerts an equal counterclockwise force on her.
PTS: 1
136. ANS:
You need to know more than just the speed. You need to know the direction the storm is traveling. You need to know not just the speed but the velocity.
PTS: 1
137. ANS:
Your displacement is zero because you are going around in a circle and end up where you started. Your velocity is not constant. You are constantly accelerating because you are constantly changing directions.
PTS: 1
138. ANS:
a. The action-reaction pairs are chain-on-wall and wall-on-chain and dog-on-chain and chain-on-dog.
b. dog-on-chain and wall-on-chain
c. The dog-on-chain force becomes greater than the wall-on-chain force and the chain moves toward the dog.
PTS: 1
Wednesday, January 9, 2008
7th Grade- Chapter 3 Online Review
7th Grade - Chapter 3 ONLINE REVEIW
True/False
Indicate whether the statement is true or false.
____ 1. A proton is a positively charged particle present in the nucleus of all atoms.
____ 2. The mass of a proton is much greater than the mass of a neutron.
____ 3. Atoms of the same element can have a different number of neutrons.
____ 4. Dalton believed that the atom was a hard sphere that was the same throughout.
____ 5. J. J. Thomson did experiments that showed that atoms cannot be divided into smaller particles.
____ 6. Rutherford’s experiment showed that alpha particles could pass through foil because most of an atom is neutrally charged.
____ 7. The strong nuclear force can hold the protons of an atom together only if the protons are far apart.
____ 8. Once a living organism dies, the amount of carbon-14 cannot be replaced.
Modified True/False
Indicate whether the statement is true or false. If false, change the identified word or phrase to make the statement true.
____ 9. The idea of the atom was first proposed by Dalton. _________________________
____ 10. An element can be identified by the number of protons in its nucleus. _________________________
____ 11. When an atom's atomic number increases during transmutation the atom has emitted a beta particle. _________________________
____ 12. The mass of an electron is about equal to the mass of a proton. _________________________
____ 13. The mass number of an element can be used to determine the number of electrons in an atom. _________________________
____ 14. Half-life is a measure of the rate of decay of an isotope. _________________________
____ 15. The number of electrons in an atom must equal the number of neutrons. _________________________
____ 16. Except for hydrogen-1, the atomic number of an isotope is always greater than the mass number. _________________________
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____ 17. Why were early philosophers’ theories about life considered only theories?
a.
People had other ideas that were more sensible.
b.
Philosophers had no evidence or proof to back up the theories.
c.
Philosophers would not share their proof with the public.
d.
Scientists did not take philosophers seriously.
____ 18. Which is NOT an example of an element?
a.
carbon
b.
gold
c.
silver
d.
sodium chloride
____ 19. Scientists often revise older scientific theories and models to account for new information. Which scientist revised his own hypothesis about the atom to account for the existence of a nucleus and proton?
a.
William Crookes
b.
John Dalton
c.
Ernest Rutherford
d.
J. J. Thompson
____ 20. Which is the most current scientific model of the atom?
a.
alpha particle model
b.
electron as wave model
c.
electron cloud model
d.
Thompson’s atomic model
____ 21. Sonal made a time line of atomic research and discovery.
How many years passed between Rutherford’s first discoveries about the atom and his first atomic model?
a.
10
b.
14
c.
19
d.
35
____ 22. What does an element’s atomic number represent?
a.
the mass of an one atom of an element
b.
the number of isotopes in the nucleus of one of its atoms
c.
the number of neutrons in the nucleus of one of its atoms
d.
the number of protons in the nucleus of one of its atoms
____ 23. Which two numbers do you need to know in order to find the number of neutrons in an isotope?
a.
atomic number and mass number
b.
atomic number and number of protons
c.
mass number and number of electrons
d.
number of protons and number of electrons
____ 24. In which type of atomic nucleus is radioactive decay most likely?
a.
nucleus with the highest mass number
b.
stable nucleus
c.
transmutated nucleus
d.
unstable nucleus with the lowest mass number
____ 25. Why would an element’s atomic number change after transmutation?
a.
It has added an alpha particle.
b.
It has expelled an alpha particle.
c.
It is no longer an isotope.
d.
It has changed into an isotope.
____ 26. Jerry is using a calendar to figure out how long an 8 g sample of iodine-131 will take to decay. It has a half life of 8 days.
If Jerry starts his experiment on March 1, on which day will he have only 1 g of iodine-131 left?
a.
March 9
b.
March 12
c.
March 25
d.
March 31
____ 27. Why would an archaeologist find it useful to know how much of the element carbon-14 is in a fossil?
a.
They can figure out how much uranium is in the fossil.
b.
They can calculate half-lives of other elements in the fossil.
c.
They can use the half life of carbon-14 to calculate when the animal lived.
d.
They can infer the size of the animal when it died.
____ 28. Which of the following is NOT a use of isotopes?
a.
to detect tumors in the body
b.
to diagnose thyroid problems in humans
c.
to store radioactive waste
d.
to tell how plants use phosphorus to grow
____ 29. Why can’t a geologist use carbon dating to find the age of a rock?
a.
Carbon-14 can only be found in things that were once alive.
b.
Carbon-14 has a different half life when found in rock.
c.
Rocks become radioactive after carbon dating.
d.
Rocks erode too quickly to perform the test.
____ 30. If two atoms have the same number of protons but different numbers of neutrons, they will have the same ____.
a.
half-life
c.
atomic number
b.
mass number
d.
degree of stability
____ 31. If an isotope has an atomic number of 25, which of the following is most likely to be its mass number?
a.
25
c.
75
b.
50
d.
100
____ 32. During beta-particle emission, a neutron splits into ____.
a.
a proton and an electron
c.
two electrons
b.
two protons
d.
two neutrons
____ 33. For a radioactive substance, half-life is determined by ____.
a.
the mass of a given sample
b.
the temperature at which the substance is stored
c.
the presence of magnetic fields
d.
none of the above
____ 34. Which particles have almost the same mass?
a.
proton and electron
c.
electron and neutron
b.
proton and neutron
d.
all three particles
____ 35. Which item best represents Dalton’s mental image of an atom?
a.
a cork
c.
a marble
b.
a candy bar with nuts
d.
a balloon full of air
____ 36. Which item best represents Thomson’s mental image of an atom?
a.
a sponge
c.
a bowling ball
b.
a chocolate-chip cookie
d.
a beach ball
____ 37. Based on his experiment, Rutherford concluded that atoms were ____.
a.
dense positively charged particles
b.
uniform throughout
c.
mainly empty space
d.
made of protons, neutrons, and electrons
____ 38. Which type of particle would NOT be deflected by a magnetic field?
a.
beta particle
c.
proton
b.
alpha particle
d.
neutron
____ 39. A transmutation involving the release of alpha particles produces atoms whose atomic number has ____.
a.
decreased by 2
c.
decreased by 1
b.
increased by 2
d.
increased by 1
____ 40. A transmutation involving the release of beta particles produces atoms whose atomic number has ____.
a.
decreased by 2
c.
decreased by 1
b.
increased by 2
d.
increased by 1
____ 41. The fluorescent screen in Rutherford’s experiment was designed to ____.
a.
detect charged particles
c.
deflect charged particles
b.
attract charged particles
d.
repel charged particles
____ 42. The nucleus is held together by ____.
a.
magnetic attraction
c.
atomic glue
b.
gravity
d.
the strong nuclear force
____ 43. A 10-g sample from a healthy 200-year-old redwood would contain ____ carbon-14 as a 10-g sample from a 20-year-old redwood sapling.
a.
one-tenth as much
c.
twice as much
b.
the same amount of
d.
half as much
____ 44. Which of the following properties of iodine-131 make it a good choice as a tracer element?
a.
It is absorbed equally by all cells in the body.
b.
It is absorbed mainly by cells in the thyroid.
c.
It has a relatively long half-life.
d.
It is a normally stable isotope.
____ 45. ____ contain(s) only one kind of atom.
a.
Matter
c.
Chemicals
b.
Elements
d.
Radioactive materials
____ 46. A(n) ____ is the basic unit of matter.
a.
electron
c.
atom
b.
molecule
d.
space
____ 47. Particles in an atom’s nucleus that do not have an electric charge are called ____.
a.
neutrons
c.
ions
b.
electrons
d.
protons
____ 48. The atomic mass of an atom consists of the mass of the ____.
a.
protons and neutrons
c.
neutrons and electrons
b.
protons and electrons
d.
neutrons, protons, and electrons
____ 49. In an atom, the electrons can be found in the ____.
a.
nucleus
c.
isotope
b.
neutron
d.
electron cloud
____ 50. J. J. Thomson used the fact that ____ charges attract each other in his cathode-ray tube experiment.
a.
like
c.
atomic
b.
neutral
d.
opposite
____ 51. The mass number of an isotope is the number of ____.
a.
electrons and protons
c.
neutrons
b.
neutrons and protons
d.
protons
____ 52. Isotopes are atoms of the same element that have a different number of ____.
a.
protons
c.
neutrons
b.
electrons
d.
nuclei
____ 53. To find the number of neutrons in an isotope, subtract the____.
a.
atomic number from the mass number
b.
mass number from the atomic number
c.
number of isotopes from the mass number
d.
number of protons from the number of electrons
____ 54. The most stable isotope of an atom with 12 protons probably has ____ neutrons.
a.
24
c.
6
b.
18
d.
12
____ 55. The strong nuclear force holds the ____ together.
a.
protons
c.
nucleus
b.
neutrons
d.
electrons
____ 56. Radioactive decay is the release of ____.
a.
radios
c.
nuclear particles and energy
b.
isotopes
d.
light
____ 57. A(n) ____ particle consists of two protons and two neutrons.
a.
gamma
c.
beta
b.
alpha
d.
omega
____ 58. The changing of one element into another in radioactive decay is called ____.
a.
transmutation
c.
half-life
b.
radiation
d.
a chain reaction
____ 59. Radioactive decay can be affected by ____.
a.
the weather
c.
increased pressure
b.
magnetic fields
d.
none of these
____ 60. A radioactive isotope has a half-life of 100 years. A sample of 40 g of the isotope will have a mass of ____ g in 200 years.
a.
120
c.
20
b.
40
d.
10
____ 61. Tracer elements can be used without danger to people because they have ____ half-lives.
a.
short
c.
strong
b.
long
d.
nonexistent
Completion
Complete each statement.
62. Most of the mass of an atom is located in its ____________________.
63. Atoms that are unstable are more likely to be ____________________ than atoms that are stable.
64. The high-energy electrons given off during radioactive decay are called ____________________.
65. Of the three main subatomic particles, the ____________________ has the least mass.
66. The type of glass tube that Crookes and Thomson used for their experiments is called a(n) ____________________ tube.
67. The stream of particles in a cathode-ray tube travels from the cathode to the ____________________.
68. The likely location of the negatively charged particles in an atom is called a(n) ____________________.
69. Atoms of the same element containing different numbers of neutrons are called ____________________.
Complete the following sentences using the terms listed below. Some terms may not be used.
atoms
anode
predictable
cathode
sphere
cloud
random
tracer elements
archaeology
chemistry
70. The study of matter is called ____________________.
71. Different elements are made up of different kinds of ____________________.
72. A(n) ____________________ is an electrode that has a positive charge.
73. A(n) ____________________ is an electrode that has a negative charge.
74. An electron cloud is shaped like a(n) ____________________ with the nucleus at its center.
75. Radioactive decay is a(n) ____________________ process.
76. Isotopes called ____________________ are used to diagnose disease and to study environmental conditions.
Choose the best of the three choices in parentheses.
77. The Greeks named what they believed to be the tiniest particle of matter a(n) ____________________ (proton, atom, cell).
78. An element is made up of only one kind of ____________________ (isotope, atom, particle).
79. Research using ____________________ (television, atomic bombs, cathode rays) led scientists to believe that the atom could be broken down into smaller particles.
80. A(n) ____________________ (electron, proton, neutron) is electrically neutral.
81. An atomic nucleus is often most stable if the number of protons is ____________________ (equal to, greater than, less than) the number of neutrons.
82. Atoms of the same element always have the same number of ____________________ (neutrons, electrons, protons).
83. To find the number of neutrons in an isotope, start with the mass number and ______________________________ (add the atomic number, subtract the atomic number, multiply by two).
84. If you have 16 g of a substance that has a half-life of 3 days, after 12 days you will have ____________________ (8, 1, 0) g of the substance remaining.
Matching
Match each isotope with the correct statement below.
a.
carbon-14
c.
iodine-131
b.
americium-241
d.
phosphorus-32
____ 85. used to study plant growth and reproduction
____ 86. used to determine the age of once-living artifacts
____ 87. used in the diagnosis of thyroid disease
____ 88. used in many smoke detectors
Match each scientist with the correct statement below.
a.
Thomson
c.
Crookes
b.
Dalton
d.
Rutherford
____ 89. Almost all the mass of an atom is located in its nucleus.
____ 90. Different elements are made of different types of atoms.
____ 91. Cathode rays are made up of negatively charged particles.
____ 92. used the cathode-ray tube to discover streams of particles
Match each item with the correct description below.
a.
neutron
h.
half-life
b.
mass number
i.
isotopes
c.
atomic number
j.
transmutation
d.
element
k.
alpha particle
e.
beta particle
l.
proton
f.
electron cloud
m.
radioactive decay
g.
electron
n.
average atomic mass
____ 93. matter that is made up of only one kind of atom
____ 94. a negatively charged particle that is part of every kind of matter
____ 95. a positively charged particle that is present in the nucleus of all atoms
____ 96. uncharged particle in the nucleus of an atom
____ 97. region surrounding the nucleus in which the electrons move about
____ 98. the number of protons in the nucleus of an atom of an element
____ 99. atoms of the same element that have different numbers of neutrons
____ 100. the number of neutrons plus protons in the nucleus of an atom
____ 101. the mass of the mixture of the isotopes for an element
____ 102. the release of nuclear particles and energy
____ 103. the changing of one element into another element through radioactive decay
____ 104. particle consisting of two protons and two neutrons
____ 105. a high-energy electron that comes from the nucleus, not from the electron cloud
____ 106. the amount of time required for half a sample of a radioactive isotope to decay
Short Answer
107.
Why do you think the electron cloud theory is the current and accepted model of the atom and how it works?
108.
It took many years and the work of many scientists to discover how atoms work.
Part A Explain why scientific collaboration and use of other scientific theories is important for the advancement of science and the development of human culture.
Part B Explain what further research about atoms and atomic theories can do for the advancement of science and human culture.
109.
Use Thomson’s cathode-ray experiments to explain why the neutron was the last of the three main subatomic particles to be discovered.
110.
Explain why an isotope with a half-life of 7 years would not be a good choice for a tracer element used to diagnose illnesses.
111.
Name three key differences between beta particles and ordinary electrons.
112.
Dalton thought that all the atoms of an element were identical. Based on what you have learned, how would you modify Dalton’s definition of an element?
113.
The model of the atom proposed by Greek philosophers appears similar to the model proposed centuries later by Dalton. What was the key difference between the two models?
114.
One isotope of helium is called helium-4. Knowing that helium has an atomic number of 2, explain why an alpha particle is sometimes referred to as a helium nucleus.
115.
How would the results of Rutherford’s metal foil experiment have been different if he had bombarded the foil with beta particles instead of alpha particles?
116.
Could carbon-14 be used to date a stone arrowhead found at an ancient burial site? Explain your reasoning.
117.
Where do the stream of particles in a cathode-ray tube come from? What provides the energy for their release?
118.
Explain why the mass of electrons can be ignored when the mass number of an atom is calculated.
119.
Suppose a scientist wants to isolate the isotopes of hydrogen (hydrogen-1, hydrogen-2, and hydrogen-3) from a sample of hydrogen. What property of the isotopes would the scientist need to rely on when designing a separation method?
120.
Suppose you had a 2-g sample of carbon-14 and a 2-g sample of iodine-131. If you used a Geiger counter to measure radioactive decay, which sample would show the larger initial rate of decay? Give a reason for your answer. How would the rates of decay change over a period of a week?
121.
Americium-241, which is used in home smoke detectors, has a half-life of about 400 years, yet manufacturers recommend discarding home smoke detectors after ten years. Could a homeowner install a smoke detector containing americium-241 and use it for decades if he or she replaces the battery once a year?
122.
The elements with atomic numbers 43 and 61 (technetium and promethium) are the only two of the elements from atomic number 1 to atomic number 83 that cannot be found in nature. What can you infer about the isotopes of technetium and promethium? Could these elements have existed in nature when Earth was first formed?
123.
The scientists who developed the modern theory of atomic structure never saw an atom. In general, on what did they base their theories?
124.
Carbon-14 dating cannot be used for nonliving materials or for materials that are older than about 50,000 years. Propose a related method scientists could use to date older, nonliving materials.
125.
Make a sketch of the solar system showing the Sun and the planets. Use the sketch to draw an analogy between the solar system and the structure of an atom. How are the two systems similar? How are they different?
Number of Subatomic Particles in Selected Isotopes
Isotope
Number of protons
Number of neutrons
Number of electrons
magnesium-24
12
magnesium-26
12
chlorine-35
18
chlorine-37
17
Table 14-1
126.
Use what you know about atomic structure to fill in the missing data in Table 14-1.
127.
Propose a model of matter that explains how atoms, which contain so much empty space, can combine to form materials such as a copper pipe or an aluminum pan that appear so solid.
128.
Suppose you were constructing a time line of developments that contributed to the modern model of the atom. Place the following events in the order that they would appear on the time line. Begin with the earliest event.
______ a. Thomson’s evidence for the existence of positive particles in atoms
______ b. Rutherford’s metal foil experiment
______ c. discovery of the neutron
______ d. the description of an atom as the smallest particle of matter
______ e. Crookes' experiments with the cathode-ray tube
129. Study the following diagram. Then label each part using the correct terms from the list.
electron
electron cloud
neutron
nucleus
proton
Use your knowledge of atomic structure to answer the following questions.
Atom
Number of protons
Number of neutrons
Number of electrons
Atomic number
Mass number
a
6
6
12
b
0
1
1
c
11
11
23
d
8
6
6
e
17
17
35
f
12
12
12
g
10
9
9
130. What are the missing values from the table?
131. Which two are isotopes of one another? Explain why they are isotopes.
132. Which two atoms could be the “before” and “after” of an alpha ejection?
133. Which atom could not possibly emit an alpha particle? Why?
134. In an outline, the subtopics are neutron, proton, and electron. What is the main topic?
135. In an outline, the subtopics are fossil dating, cancer detection, and circulation problems. What is the main topic?
136. An atom has a mass number of 53 and an atomic number of 26. How many neutrons does it have? Include a formula that explains your calculation.
137. The isotopes of carbon (carbon-12, carbon-13, and carbon-14) have different mass numbers. Each isotope has six protons. Explain how you can determine the number of neutrons in each isotope.
138. A certain element has a half-life of 20 years. A scientist starts with 100 g of the element.
a. How many grams remain after 20 years?
b. How many grams remain after 40 years?
c. How many half-lives are there in a 100-year span? How many grams of the sample would remain at the end of the 100 years?
Problem
Figure 14-1
139.
Figure 14-1 shows the decay of a sample of neptunium-238 over a period of 10 days. What is the half-life of neptunium-238?
140.
If the original sample in Figure 14-1 contains 0.620 g, how much neptunium-238 will remain after 4 days? How much will remain after 8 days?
141.
Uranium is the element with atomic number 92. Uranium-235 is a radioactive isotope that decays by emitting alpha particles. What is the atomic number of the new element that forms? What is its mass number?
142.
Thorium is the element with atomic number 90. Thorium-231 is a radioactive isotope that decays by emitting beta particles. What is the atomic number of the new element that forms? What is its mass number?
Essay
143. How is americium-241 used in smoke detectors?
7th Grade - Chapter 3 ONLINE REVEIW
Answer Section
TRUE/FALSE
1. ANS: T PTS: 1
2. ANS: F PTS: 1
3. ANS: T PTS: 1
4. ANS: T PTS: 1
5. ANS: F PTS: 1
6. ANS: F PTS: 1
7. ANS: F PTS: 1
8. ANS: T PTS: 1
MODIFIED TRUE/FALSE
9. ANS: F, ancient Greeks
PTS: 1 DIF: Webb's I OBJ: 2/1 STA: SC.H.1.3.6 SC.H.3.3.5
10. ANS: T PTS: 1 DIF: Webb's I
OBJ: 3/1 STA: SC.A.1.3.1 SC.A.2.3.2
11. ANS: T PTS: 1 DIF: Webb's I
OBJ: 5/2 STA: SC.A.2.3.2
12. ANS: F, neutron
PTS: 1 DIF: Webb's I OBJ: 3/1 STA: SC.A.2.3.2
13. ANS: F, atomic number
PTS: 1 DIF: Webb's I OBJ: 3/1 STA: SC.A.2.3.2
14. ANS: T PTS: 1 DIF: Webb's I
OBJ: 5/2
15. ANS: F, protons
PTS: 1 DIF: Webb's I OBJ: 3/1 STA: SC.A.2.3.2
16. ANS: F, less
PTS: 1 DIF: Webb's I OBJ: 3/1 STA: SC.A.2.3.2
MULTIPLE CHOICE
17. ANS: B PTS: 1 DIF: Webb's II STA: SC.H.1.3.1
18. ANS: D PTS: 1 DIF: Webb's I STA: SC.A.1.3.1
19. ANS: C PTS: 1 DIF: Webb's I STA: SC.H.1.3.1
20. ANS: C PTS: 1 DIF: Webb's I STA: SC.H.1.3.1 SC.A.2.3.2
21. ANS: B PTS: 1 DIF: Webb's II
STA: SC.H.1.3.1 SC.H.1.3.6 SC.H.3.3.5
22. ANS: D PTS: 1 DIF: Webb's I STA: SC.A.2.3.2
23. ANS: A PTS: 1 DIF: Webb's I STA: SC.A.2.3.2
24. ANS: D PTS: 1 DIF: Webb's II STA: SC.A.2.3.2
25. ANS: B PTS: 1 DIF: Webb's II STA: SC.A.2.3.2
26. ANS: C PTS: 1 DIF: Webb's II STA: SC.A.2.3.2 SC.D.1.3.5
27. ANS: C PTS: 1 DIF: Webb's II STA: SC.A.2.3.2 SC.D.1.3.5
28. ANS: C PTS: 1 DIF: Webb's I
29. ANS: A PTS: 1 DIF: Webb's II STA: SC.A.1.3.1
30. ANS: C PTS: 1 DIF: Webb's I OBJ: 3/1
STA: SC.A.2.3.2
31. ANS: B PTS: 1 DIF: Webb's I OBJ: 3/1
32. ANS: A PTS: 1 DIF: Webb's I OBJ: 5/2
STA: SC.A.2.3.2
33. ANS: D PTS: 1 DIF: Webb's I OBJ: 5/2
34. ANS: B PTS: 1 DIF: Webb's I OBJ: 3/1
STA: SC.A.2.3.2
35. ANS: C PTS: 1 DIF: Webb's I OBJ: 2/1
STA: SC.H.1.3.1 SC.H.1.3.6
36. ANS: B PTS: 1 DIF: Webb's I OBJ: 2/1
STA: SC.H.1.3.1 SC.H.1.3.6
37. ANS: C PTS: 1 DIF: Webb's I OBJ: 2/1
STA: SC.H.1.3.1 SC.H.1.3.6
38. ANS: D PTS: 1 DIF: Webb's II OBJ: 1/1
STA: SC.A.2.3.1 SC.A.2.3.2
39. ANS: A PTS: 1 DIF: Webb's I OBJ: 5/2
STA: SC.A.2.3.2
40. ANS: D PTS: 1 DIF: Webb's I OBJ: 5/2
STA: SC.A.2.3.2
41. ANS: A PTS: 1 DIF: Webb's I OBJ: 1/1
STA: SC.H.1.3.1 SC.H.1.3.6
42. ANS: D PTS: 1 DIF: Webb's I OBJ: 3/1
STA: SC.A.2.3.2
43. ANS: B PTS: 1 DIF: Webb's I OBJ: 5/2
44. ANS: B PTS: 1 DIF: Webb's I OBJ: 6/2
45. ANS: B PTS: 1
46. ANS: C PTS: 1
47. ANS: A PTS: 1
48. ANS: A PTS: 1
49. ANS: D PTS: 1
50. ANS: D PTS: 1
51. ANS: B PTS: 1
52. ANS: C PTS: 1
53. ANS: A PTS: 1
54. ANS: D PTS: 1
55. ANS: C PTS: 1
56. ANS: C PTS: 1
57. ANS: B PTS: 1
58. ANS: A PTS: 1
59. ANS: D PTS: 1
60. ANS: D PTS: 1
61. ANS: A PTS: 1
COMPLETION
62. ANS: nucleus
PTS: 1 DIF: Webb's I OBJ: 3/1 STA: SC.A.2.3.2
63. ANS: radioactive
PTS: 1 DIF: Webb's I OBJ: 4/1 STA: SC.A.2.3.2
64. ANS: beta particles
PTS: 1 DIF: Webb's I OBJ: 4/1 STA: SC.A.2.3.2
65. ANS: electron
PTS: 1 DIF: Webb's I OBJ: 3/1 STA: SC.A.2.3.2
66. ANS: cathode-ray
PTS: 1 DIF: Webb's I OBJ: 1/1 STA: SC.H.1.3.6
67. ANS: anode
PTS: 1 DIF: Webb's I OBJ: 1/1
68. ANS: electron cloud
PTS: 1 DIF: Webb's I OBJ: 3/1 STA: SC.A.2.3.2
69. ANS: isotopes
PTS: 1 DIF: Webb's I OBJ: 5/2 STA: SC.A.2.3.2
70. ANS: chemistry
PTS: 1
71. ANS: atoms
PTS: 1
72. ANS: anode
PTS: 1
73. ANS: cathode
PTS: 1
74. ANS: sphere
PTS: 1
75. ANS: random
PTS: 1
76. ANS: tracer elements
PTS: 1
77. ANS: atom
PTS: 1
78. ANS: atom
PTS: 1
79. ANS: cathode rays
PTS: 1
80. ANS: neutron
PTS: 1
81. ANS: equal to
PTS: 1
82. ANS: protons
PTS: 1
83. ANS: subtract the atomic number
PTS: 1
84. ANS: 1
PTS: 1
MATCHING
85. ANS: D PTS: 1 DIF: Webb's I OBJ: 6/2
86. ANS: A PTS: 1 DIF: Webb's I OBJ: 6/2
87. ANS: C PTS: 1 DIF: Webb's I OBJ: 6/2
88. ANS: B PTS: 1 DIF: Webb's I OBJ: 6/2
89. ANS: D PTS: 1 DIF: Webb's I OBJ: 2/1
STA: SC.A.2.3.2
90. ANS: B PTS: 1 DIF: Webb's I OBJ: 2/1
STA: SC.A.2.3.2
91. ANS: A PTS: 1 DIF: Webb's I OBJ: 1/1
STA: SC.A.2.3.1 SC.A.2.3.2
92. ANS: C PTS: 1 DIF: Webb's I OBJ: 1/1
STA: SC.A.2.3.1 SC.A.2.3.2
93. ANS: D PTS: 1
94. ANS: G PTS: 1
95. ANS: L PTS: 1
96. ANS: A PTS: 1
97. ANS: F PTS: 1
98. ANS: C PTS: 1
99. ANS: I PTS: 1
100. ANS: B PTS: 1
101. ANS: N PTS: 1
102. ANS: M PTS: 1
103. ANS: J PTS: 1
104. ANS: K PTS: 1
105. ANS: E PTS: 1
106. ANS: H PTS: 1
SHORT ANSWER
107. ANS:
The theory accounts for recent research that explains the unpredictable nature of electrons. The behavior of electrons is more comparable to that of waves than of particles. Electrons are also more likely to be found close to the nucleus because they are attracted to the positive charges of the protons. The electrons in the region surrounding the nucleus create a cloud-like appearance, which explains the name “electron cloud model.”
PTS: 1 DIF: Webb's II STA: SC.A.2.3.2 SC.H.1.3.1
108. ANS:
Part A Answers will vary, but may include the idea that scientific theories often build on each other over time. For example, one scientist may make discoveries about protons, enabling another group of scientists to do further research. Further research may uncover information about neutrons or other related information. This helps advance science and human culture by providing people with more general knowledge about life.
Part B Further exploration about atoms and atomic theories enables general scientific knowledge to increase. It also allows for possible cures for diseases and can save many lives.
PTS: 1 DIF: Webb's III STA: SC.H.1.3.6 SC.H.3.3.5
109. ANS:
Thomson used magnetic fields to detect charged particles in his cathode-ray tube. Because neutrons have no charge, the cathode-ray tube did not detect them.
PTS: 1 DIF: Webb's II OBJ: 1/1 STA: SC.H.1.3.1 SC.H.1.3.6
110. ANS:
A small quantity of the isotope would not decay quickly enough to produce the desired effect, if the isotope were absorbed into body tissues, the patient would be exposed to a prolonged and most likely damaging, dose of radiation.
PTS: 1 DIF: Webb's II OBJ: 6/2 STA: SC.A.2.3.3
111. ANS:
Beta particles 1) are emitted from the atom during radioactive decay, 2) originate in the nucleus when a neutron splits into a proton and electron, and 3) have higher energies than ordinary electrons.
PTS: 1 DIF: Webb's II OBJ: 5/2 STA: SC.A.2.3.2
112. ANS:
All atoms of an element are not identical. Many elements have more than one isotope. Although each atom of an element has the same number of protons, the numbers of neutrons in the atom's nucleus can vary.
PTS: 1 DIF: Webb's II OBJ: 2/1
STA: SC.A.2.3.2 SC.H.1.3.1 SC.H.1.3.6
113. ANS:
Dalton’s model was based on scientific research and open to challenge by further studies. The Greeks used logic, but they did not do experiments. Dalton also added the idea of different atoms for different elements.
PTS: 1 DIF: Webb's II OBJ: 2/1 STA: SC.H.1.3.1 SC.H.1.3.6
114. ANS:
An alpha particle consists of two protons and two neutrons, the same four particles as in a helium-4 nucleus (mass number 4 – atomic number 2).
PTS: 1 DIF: Webb's II OBJ: 5/2 STA: SC.A.2.3.2
115. ANS:
The paths of beta particles that passed near the nucleus would have been deflected in a different direction because of the force of attraction between the electrons and protons.
PTS: 1 DIF: Webb's II OBJ: 1/1 STA: SC.A.2.3.2
116. ANS:
No, carbon-14 can be used to date objects that were once alive, not objects like stone that were never alive. An organism had to absorb carbon-14 as a natural part of metabolism so that the decay process could begin when it died.
PTS: 1 DIF: Webb's II OBJ: 5/2
117. ANS:
The stream of particles are emitted by the cathode. The high-voltage electrical source supplies the energy for their release.
PTS: 1 DIF: Webb's II OBJ: 1/1 STA: SC.A.2.3.1
118. ANS:
Protons and neutrons in the nucleus account for almost all the mass of an atom. The electrons are almost without mass and perhaps can be explained as waves rather than particles.
PTS: 1 DIF: Webb's II OBJ: 3/1 STA: SC.A.2.3.2
119. ANS:
The scientist would need to rely on the difference in mass.
PTS: 1 DIF: Webb's II OBJ: 5/2
120. ANS:
The iodine-131 would show the larger initial decay because it has a much shorter half-life. The decay of iodine-131 would drop off dramatically during the week; there would be no noticeable change in decay for the carbon-14 sample.
PTS: 1 DIF: Webb's II OBJ: 6/2
121. ANS:
Theoretically, an isotope with a half-life of 400 years should provide enough alpha particles to allow the smoke detector to work for many more years. However, the sample of americium-241 in the detector may be so small that the number of alpha particles emitted drops below the needed level. Also, the reliability of other parts in the detector may be limited to ten years. The smoke detector should be replaced.
PTS: 1 DIF: Webb's II OBJ: 6/2
122. ANS:
Technetium and promethium have no stable isotopes. These two elements could have existed long ago, but any deposits of these elements have long since decayed.
PTS: 1 DIF: Webb's II OBJ: 5/2
123. ANS:
They based their theories on the observed behavior of atoms and of subatomic particles. For example, they couldn’t see an electron, but they could observe behavior of electrons in a cathode-ray tube. As they learned more about the behavior, they modified their theories.
PTS: 1 DIF: Webb's II OBJ: 2/1 STA: SC.H.1.3.1 SC.H.1.3.3
124. ANS:
Find a radioactive isotope of an element that is commonly found in rocks. The isotope would need to have a long half-life.
PTS: 1 DIF: Webb's II OBJ: 6/2
125. ANS:
Students may compare the Sun and the planets to the nucleus and electrons. The gravitational attraction between the Sun and planets can be compared to the attraction between electrons and protons in the nucleus. There is a lot of empty space in both systems. Unlike electrons, the planets are not identical. In contrast to the electron cloud, the location of the planets in relation to the Sun is definite. Electrons are likely to be close to the nucleus, but they could be anywhere.
PTS: 1 DIF: Webb's III OBJ: 3/1 STA: SC.A.2.3.2 SC.E.1.3.1
126. ANS:
Number of Subatomic Particles in Selected Isotopes
Isotope
Number of protons
Number of neutrons
Number of electrons
magnesium-24
12
12
12
magnesium-26
12
14
12
chlorine-35
17
18
17
chlorine-37
17
20
17
PTS: 1 DIF: Webb's II OBJ: 5/2 STA: SC.A.2.3.2
127. ANS:
Students’ models will probably focus on the large number of atoms and their possible arrangements. One possible analogy could use a chain link fence. With a single layer of fencing, the holes in the fence are obvious and easy to penetrate. With multiple layers placed one on top of the other, the structure becomes more solid and a path through the layers much less direct.
PTS: 1 DIF: Webb's III OBJ: 3/1 STA: SC.A.2.3.2
128. ANS:
D, E, A, B, C
PTS: 1 DIF: Webb's II OBJ: 2/1 STA: SC.H.1.3.6
129. ANS:
PTS: 1
130. ANS:
a. 6, 6
b. 1, 1
c. 12, 11
d. 6, 14
e. 18, 17
f. 12, 24
g. 9, 19
PTS: 1
131. ANS:
Atom a and atom d are isotopes. They have the same atomic number, or number of protons, but different mass numbers because the number of neutrons is different.
PTS: 1
132. ANS:
Atom c could be the “before” of an alpha ejection, and atom g could be the “after.”
PTS: 1
133. ANS:
Atom b, which has one proton and no neutrons, could not possibly emit an alpha particle, which consists of two protons and two neutrons.
PTS: 1
134. ANS:
Answers will vary slightly. Topics should indicate that neutrons, protons, and electrons are particles within atoms.
PTS: 1
135. ANS:
Answers will vary slightly. Topics should indicate uses of radioactive isotopes.
PTS: 1
136. ANS:
number of neutrons = mass number – atomic number
53 – 26 = 27
PTS: 1
137. ANS:
The number of neutrons in an atom, including isotopes of the same element, can be calculated by subtracting the atomic number from the mass number.
For carbon-12: number of neutrons = 12 – 6 = 6
For carbon-13: number of neutrons = 13 – 6 = 7
For carbon-14: number of neutrons = 14 – 6 = 8
PTS: 1
138. ANS:
PTS: 1
PROBLEM
139. ANS:
2 days
PTS: 1 DIF: Webb's II OBJ: 5/2
140. ANS:
0.155 g; 0.0388 g
PTS: 1 DIF: Webb's II OBJ: 5/2
141. ANS:
atomic number = 90; mass number = 231
PTS: 1 DIF: Webb's II OBJ: 5/2 STA: SC.A.2.3.2
142. ANS:
atomic number = 91; mass number = 231
PTS: 1 DIF: Webb's II OBJ: 4/1 STA: SC.A.2.3.2
ESSAY
143. ANS:
Americium-241 undergoes transmutation to neptunium by ejecting an alpha particle. The air in a smoke detector can conduct electricity because of the presence of the alpha particles. As long as the electric current flows, the smoke detector stays silent. If smoke enters the detector, the current is interrupted and the alarm sounds.
PTS: 1
True/False
Indicate whether the statement is true or false.
____ 1. A proton is a positively charged particle present in the nucleus of all atoms.
____ 2. The mass of a proton is much greater than the mass of a neutron.
____ 3. Atoms of the same element can have a different number of neutrons.
____ 4. Dalton believed that the atom was a hard sphere that was the same throughout.
____ 5. J. J. Thomson did experiments that showed that atoms cannot be divided into smaller particles.
____ 6. Rutherford’s experiment showed that alpha particles could pass through foil because most of an atom is neutrally charged.
____ 7. The strong nuclear force can hold the protons of an atom together only if the protons are far apart.
____ 8. Once a living organism dies, the amount of carbon-14 cannot be replaced.
Modified True/False
Indicate whether the statement is true or false. If false, change the identified word or phrase to make the statement true.
____ 9. The idea of the atom was first proposed by Dalton. _________________________
____ 10. An element can be identified by the number of protons in its nucleus. _________________________
____ 11. When an atom's atomic number increases during transmutation the atom has emitted a beta particle. _________________________
____ 12. The mass of an electron is about equal to the mass of a proton. _________________________
____ 13. The mass number of an element can be used to determine the number of electrons in an atom. _________________________
____ 14. Half-life is a measure of the rate of decay of an isotope. _________________________
____ 15. The number of electrons in an atom must equal the number of neutrons. _________________________
____ 16. Except for hydrogen-1, the atomic number of an isotope is always greater than the mass number. _________________________
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____ 17. Why were early philosophers’ theories about life considered only theories?
a.
People had other ideas that were more sensible.
b.
Philosophers had no evidence or proof to back up the theories.
c.
Philosophers would not share their proof with the public.
d.
Scientists did not take philosophers seriously.
____ 18. Which is NOT an example of an element?
a.
carbon
b.
gold
c.
silver
d.
sodium chloride
____ 19. Scientists often revise older scientific theories and models to account for new information. Which scientist revised his own hypothesis about the atom to account for the existence of a nucleus and proton?
a.
William Crookes
b.
John Dalton
c.
Ernest Rutherford
d.
J. J. Thompson
____ 20. Which is the most current scientific model of the atom?
a.
alpha particle model
b.
electron as wave model
c.
electron cloud model
d.
Thompson’s atomic model
____ 21. Sonal made a time line of atomic research and discovery.
How many years passed between Rutherford’s first discoveries about the atom and his first atomic model?
a.
10
b.
14
c.
19
d.
35
____ 22. What does an element’s atomic number represent?
a.
the mass of an one atom of an element
b.
the number of isotopes in the nucleus of one of its atoms
c.
the number of neutrons in the nucleus of one of its atoms
d.
the number of protons in the nucleus of one of its atoms
____ 23. Which two numbers do you need to know in order to find the number of neutrons in an isotope?
a.
atomic number and mass number
b.
atomic number and number of protons
c.
mass number and number of electrons
d.
number of protons and number of electrons
____ 24. In which type of atomic nucleus is radioactive decay most likely?
a.
nucleus with the highest mass number
b.
stable nucleus
c.
transmutated nucleus
d.
unstable nucleus with the lowest mass number
____ 25. Why would an element’s atomic number change after transmutation?
a.
It has added an alpha particle.
b.
It has expelled an alpha particle.
c.
It is no longer an isotope.
d.
It has changed into an isotope.
____ 26. Jerry is using a calendar to figure out how long an 8 g sample of iodine-131 will take to decay. It has a half life of 8 days.
If Jerry starts his experiment on March 1, on which day will he have only 1 g of iodine-131 left?
a.
March 9
b.
March 12
c.
March 25
d.
March 31
____ 27. Why would an archaeologist find it useful to know how much of the element carbon-14 is in a fossil?
a.
They can figure out how much uranium is in the fossil.
b.
They can calculate half-lives of other elements in the fossil.
c.
They can use the half life of carbon-14 to calculate when the animal lived.
d.
They can infer the size of the animal when it died.
____ 28. Which of the following is NOT a use of isotopes?
a.
to detect tumors in the body
b.
to diagnose thyroid problems in humans
c.
to store radioactive waste
d.
to tell how plants use phosphorus to grow
____ 29. Why can’t a geologist use carbon dating to find the age of a rock?
a.
Carbon-14 can only be found in things that were once alive.
b.
Carbon-14 has a different half life when found in rock.
c.
Rocks become radioactive after carbon dating.
d.
Rocks erode too quickly to perform the test.
____ 30. If two atoms have the same number of protons but different numbers of neutrons, they will have the same ____.
a.
half-life
c.
atomic number
b.
mass number
d.
degree of stability
____ 31. If an isotope has an atomic number of 25, which of the following is most likely to be its mass number?
a.
25
c.
75
b.
50
d.
100
____ 32. During beta-particle emission, a neutron splits into ____.
a.
a proton and an electron
c.
two electrons
b.
two protons
d.
two neutrons
____ 33. For a radioactive substance, half-life is determined by ____.
a.
the mass of a given sample
b.
the temperature at which the substance is stored
c.
the presence of magnetic fields
d.
none of the above
____ 34. Which particles have almost the same mass?
a.
proton and electron
c.
electron and neutron
b.
proton and neutron
d.
all three particles
____ 35. Which item best represents Dalton’s mental image of an atom?
a.
a cork
c.
a marble
b.
a candy bar with nuts
d.
a balloon full of air
____ 36. Which item best represents Thomson’s mental image of an atom?
a.
a sponge
c.
a bowling ball
b.
a chocolate-chip cookie
d.
a beach ball
____ 37. Based on his experiment, Rutherford concluded that atoms were ____.
a.
dense positively charged particles
b.
uniform throughout
c.
mainly empty space
d.
made of protons, neutrons, and electrons
____ 38. Which type of particle would NOT be deflected by a magnetic field?
a.
beta particle
c.
proton
b.
alpha particle
d.
neutron
____ 39. A transmutation involving the release of alpha particles produces atoms whose atomic number has ____.
a.
decreased by 2
c.
decreased by 1
b.
increased by 2
d.
increased by 1
____ 40. A transmutation involving the release of beta particles produces atoms whose atomic number has ____.
a.
decreased by 2
c.
decreased by 1
b.
increased by 2
d.
increased by 1
____ 41. The fluorescent screen in Rutherford’s experiment was designed to ____.
a.
detect charged particles
c.
deflect charged particles
b.
attract charged particles
d.
repel charged particles
____ 42. The nucleus is held together by ____.
a.
magnetic attraction
c.
atomic glue
b.
gravity
d.
the strong nuclear force
____ 43. A 10-g sample from a healthy 200-year-old redwood would contain ____ carbon-14 as a 10-g sample from a 20-year-old redwood sapling.
a.
one-tenth as much
c.
twice as much
b.
the same amount of
d.
half as much
____ 44. Which of the following properties of iodine-131 make it a good choice as a tracer element?
a.
It is absorbed equally by all cells in the body.
b.
It is absorbed mainly by cells in the thyroid.
c.
It has a relatively long half-life.
d.
It is a normally stable isotope.
____ 45. ____ contain(s) only one kind of atom.
a.
Matter
c.
Chemicals
b.
Elements
d.
Radioactive materials
____ 46. A(n) ____ is the basic unit of matter.
a.
electron
c.
atom
b.
molecule
d.
space
____ 47. Particles in an atom’s nucleus that do not have an electric charge are called ____.
a.
neutrons
c.
ions
b.
electrons
d.
protons
____ 48. The atomic mass of an atom consists of the mass of the ____.
a.
protons and neutrons
c.
neutrons and electrons
b.
protons and electrons
d.
neutrons, protons, and electrons
____ 49. In an atom, the electrons can be found in the ____.
a.
nucleus
c.
isotope
b.
neutron
d.
electron cloud
____ 50. J. J. Thomson used the fact that ____ charges attract each other in his cathode-ray tube experiment.
a.
like
c.
atomic
b.
neutral
d.
opposite
____ 51. The mass number of an isotope is the number of ____.
a.
electrons and protons
c.
neutrons
b.
neutrons and protons
d.
protons
____ 52. Isotopes are atoms of the same element that have a different number of ____.
a.
protons
c.
neutrons
b.
electrons
d.
nuclei
____ 53. To find the number of neutrons in an isotope, subtract the____.
a.
atomic number from the mass number
b.
mass number from the atomic number
c.
number of isotopes from the mass number
d.
number of protons from the number of electrons
____ 54. The most stable isotope of an atom with 12 protons probably has ____ neutrons.
a.
24
c.
6
b.
18
d.
12
____ 55. The strong nuclear force holds the ____ together.
a.
protons
c.
nucleus
b.
neutrons
d.
electrons
____ 56. Radioactive decay is the release of ____.
a.
radios
c.
nuclear particles and energy
b.
isotopes
d.
light
____ 57. A(n) ____ particle consists of two protons and two neutrons.
a.
gamma
c.
beta
b.
alpha
d.
omega
____ 58. The changing of one element into another in radioactive decay is called ____.
a.
transmutation
c.
half-life
b.
radiation
d.
a chain reaction
____ 59. Radioactive decay can be affected by ____.
a.
the weather
c.
increased pressure
b.
magnetic fields
d.
none of these
____ 60. A radioactive isotope has a half-life of 100 years. A sample of 40 g of the isotope will have a mass of ____ g in 200 years.
a.
120
c.
20
b.
40
d.
10
____ 61. Tracer elements can be used without danger to people because they have ____ half-lives.
a.
short
c.
strong
b.
long
d.
nonexistent
Completion
Complete each statement.
62. Most of the mass of an atom is located in its ____________________.
63. Atoms that are unstable are more likely to be ____________________ than atoms that are stable.
64. The high-energy electrons given off during radioactive decay are called ____________________.
65. Of the three main subatomic particles, the ____________________ has the least mass.
66. The type of glass tube that Crookes and Thomson used for their experiments is called a(n) ____________________ tube.
67. The stream of particles in a cathode-ray tube travels from the cathode to the ____________________.
68. The likely location of the negatively charged particles in an atom is called a(n) ____________________.
69. Atoms of the same element containing different numbers of neutrons are called ____________________.
Complete the following sentences using the terms listed below. Some terms may not be used.
atoms
anode
predictable
cathode
sphere
cloud
random
tracer elements
archaeology
chemistry
70. The study of matter is called ____________________.
71. Different elements are made up of different kinds of ____________________.
72. A(n) ____________________ is an electrode that has a positive charge.
73. A(n) ____________________ is an electrode that has a negative charge.
74. An electron cloud is shaped like a(n) ____________________ with the nucleus at its center.
75. Radioactive decay is a(n) ____________________ process.
76. Isotopes called ____________________ are used to diagnose disease and to study environmental conditions.
Choose the best of the three choices in parentheses.
77. The Greeks named what they believed to be the tiniest particle of matter a(n) ____________________ (proton, atom, cell).
78. An element is made up of only one kind of ____________________ (isotope, atom, particle).
79. Research using ____________________ (television, atomic bombs, cathode rays) led scientists to believe that the atom could be broken down into smaller particles.
80. A(n) ____________________ (electron, proton, neutron) is electrically neutral.
81. An atomic nucleus is often most stable if the number of protons is ____________________ (equal to, greater than, less than) the number of neutrons.
82. Atoms of the same element always have the same number of ____________________ (neutrons, electrons, protons).
83. To find the number of neutrons in an isotope, start with the mass number and ______________________________ (add the atomic number, subtract the atomic number, multiply by two).
84. If you have 16 g of a substance that has a half-life of 3 days, after 12 days you will have ____________________ (8, 1, 0) g of the substance remaining.
Matching
Match each isotope with the correct statement below.
a.
carbon-14
c.
iodine-131
b.
americium-241
d.
phosphorus-32
____ 85. used to study plant growth and reproduction
____ 86. used to determine the age of once-living artifacts
____ 87. used in the diagnosis of thyroid disease
____ 88. used in many smoke detectors
Match each scientist with the correct statement below.
a.
Thomson
c.
Crookes
b.
Dalton
d.
Rutherford
____ 89. Almost all the mass of an atom is located in its nucleus.
____ 90. Different elements are made of different types of atoms.
____ 91. Cathode rays are made up of negatively charged particles.
____ 92. used the cathode-ray tube to discover streams of particles
Match each item with the correct description below.
a.
neutron
h.
half-life
b.
mass number
i.
isotopes
c.
atomic number
j.
transmutation
d.
element
k.
alpha particle
e.
beta particle
l.
proton
f.
electron cloud
m.
radioactive decay
g.
electron
n.
average atomic mass
____ 93. matter that is made up of only one kind of atom
____ 94. a negatively charged particle that is part of every kind of matter
____ 95. a positively charged particle that is present in the nucleus of all atoms
____ 96. uncharged particle in the nucleus of an atom
____ 97. region surrounding the nucleus in which the electrons move about
____ 98. the number of protons in the nucleus of an atom of an element
____ 99. atoms of the same element that have different numbers of neutrons
____ 100. the number of neutrons plus protons in the nucleus of an atom
____ 101. the mass of the mixture of the isotopes for an element
____ 102. the release of nuclear particles and energy
____ 103. the changing of one element into another element through radioactive decay
____ 104. particle consisting of two protons and two neutrons
____ 105. a high-energy electron that comes from the nucleus, not from the electron cloud
____ 106. the amount of time required for half a sample of a radioactive isotope to decay
Short Answer
107.
Why do you think the electron cloud theory is the current and accepted model of the atom and how it works?
108.
It took many years and the work of many scientists to discover how atoms work.
Part A Explain why scientific collaboration and use of other scientific theories is important for the advancement of science and the development of human culture.
Part B Explain what further research about atoms and atomic theories can do for the advancement of science and human culture.
109.
Use Thomson’s cathode-ray experiments to explain why the neutron was the last of the three main subatomic particles to be discovered.
110.
Explain why an isotope with a half-life of 7 years would not be a good choice for a tracer element used to diagnose illnesses.
111.
Name three key differences between beta particles and ordinary electrons.
112.
Dalton thought that all the atoms of an element were identical. Based on what you have learned, how would you modify Dalton’s definition of an element?
113.
The model of the atom proposed by Greek philosophers appears similar to the model proposed centuries later by Dalton. What was the key difference between the two models?
114.
One isotope of helium is called helium-4. Knowing that helium has an atomic number of 2, explain why an alpha particle is sometimes referred to as a helium nucleus.
115.
How would the results of Rutherford’s metal foil experiment have been different if he had bombarded the foil with beta particles instead of alpha particles?
116.
Could carbon-14 be used to date a stone arrowhead found at an ancient burial site? Explain your reasoning.
117.
Where do the stream of particles in a cathode-ray tube come from? What provides the energy for their release?
118.
Explain why the mass of electrons can be ignored when the mass number of an atom is calculated.
119.
Suppose a scientist wants to isolate the isotopes of hydrogen (hydrogen-1, hydrogen-2, and hydrogen-3) from a sample of hydrogen. What property of the isotopes would the scientist need to rely on when designing a separation method?
120.
Suppose you had a 2-g sample of carbon-14 and a 2-g sample of iodine-131. If you used a Geiger counter to measure radioactive decay, which sample would show the larger initial rate of decay? Give a reason for your answer. How would the rates of decay change over a period of a week?
121.
Americium-241, which is used in home smoke detectors, has a half-life of about 400 years, yet manufacturers recommend discarding home smoke detectors after ten years. Could a homeowner install a smoke detector containing americium-241 and use it for decades if he or she replaces the battery once a year?
122.
The elements with atomic numbers 43 and 61 (technetium and promethium) are the only two of the elements from atomic number 1 to atomic number 83 that cannot be found in nature. What can you infer about the isotopes of technetium and promethium? Could these elements have existed in nature when Earth was first formed?
123.
The scientists who developed the modern theory of atomic structure never saw an atom. In general, on what did they base their theories?
124.
Carbon-14 dating cannot be used for nonliving materials or for materials that are older than about 50,000 years. Propose a related method scientists could use to date older, nonliving materials.
125.
Make a sketch of the solar system showing the Sun and the planets. Use the sketch to draw an analogy between the solar system and the structure of an atom. How are the two systems similar? How are they different?
Number of Subatomic Particles in Selected Isotopes
Isotope
Number of protons
Number of neutrons
Number of electrons
magnesium-24
12
magnesium-26
12
chlorine-35
18
chlorine-37
17
Table 14-1
126.
Use what you know about atomic structure to fill in the missing data in Table 14-1.
127.
Propose a model of matter that explains how atoms, which contain so much empty space, can combine to form materials such as a copper pipe or an aluminum pan that appear so solid.
128.
Suppose you were constructing a time line of developments that contributed to the modern model of the atom. Place the following events in the order that they would appear on the time line. Begin with the earliest event.
______ a. Thomson’s evidence for the existence of positive particles in atoms
______ b. Rutherford’s metal foil experiment
______ c. discovery of the neutron
______ d. the description of an atom as the smallest particle of matter
______ e. Crookes' experiments with the cathode-ray tube
129. Study the following diagram. Then label each part using the correct terms from the list.
electron
electron cloud
neutron
nucleus
proton
Use your knowledge of atomic structure to answer the following questions.
Atom
Number of protons
Number of neutrons
Number of electrons
Atomic number
Mass number
a
6
6
12
b
0
1
1
c
11
11
23
d
8
6
6
e
17
17
35
f
12
12
12
g
10
9
9
130. What are the missing values from the table?
131. Which two are isotopes of one another? Explain why they are isotopes.
132. Which two atoms could be the “before” and “after” of an alpha ejection?
133. Which atom could not possibly emit an alpha particle? Why?
134. In an outline, the subtopics are neutron, proton, and electron. What is the main topic?
135. In an outline, the subtopics are fossil dating, cancer detection, and circulation problems. What is the main topic?
136. An atom has a mass number of 53 and an atomic number of 26. How many neutrons does it have? Include a formula that explains your calculation.
137. The isotopes of carbon (carbon-12, carbon-13, and carbon-14) have different mass numbers. Each isotope has six protons. Explain how you can determine the number of neutrons in each isotope.
138. A certain element has a half-life of 20 years. A scientist starts with 100 g of the element.
a. How many grams remain after 20 years?
b. How many grams remain after 40 years?
c. How many half-lives are there in a 100-year span? How many grams of the sample would remain at the end of the 100 years?
Problem
Figure 14-1
139.
Figure 14-1 shows the decay of a sample of neptunium-238 over a period of 10 days. What is the half-life of neptunium-238?
140.
If the original sample in Figure 14-1 contains 0.620 g, how much neptunium-238 will remain after 4 days? How much will remain after 8 days?
141.
Uranium is the element with atomic number 92. Uranium-235 is a radioactive isotope that decays by emitting alpha particles. What is the atomic number of the new element that forms? What is its mass number?
142.
Thorium is the element with atomic number 90. Thorium-231 is a radioactive isotope that decays by emitting beta particles. What is the atomic number of the new element that forms? What is its mass number?
Essay
143. How is americium-241 used in smoke detectors?
7th Grade - Chapter 3 ONLINE REVEIW
Answer Section
TRUE/FALSE
1. ANS: T PTS: 1
2. ANS: F PTS: 1
3. ANS: T PTS: 1
4. ANS: T PTS: 1
5. ANS: F PTS: 1
6. ANS: F PTS: 1
7. ANS: F PTS: 1
8. ANS: T PTS: 1
MODIFIED TRUE/FALSE
9. ANS: F, ancient Greeks
PTS: 1 DIF: Webb's I OBJ: 2/1 STA: SC.H.1.3.6 SC.H.3.3.5
10. ANS: T PTS: 1 DIF: Webb's I
OBJ: 3/1 STA: SC.A.1.3.1 SC.A.2.3.2
11. ANS: T PTS: 1 DIF: Webb's I
OBJ: 5/2 STA: SC.A.2.3.2
12. ANS: F, neutron
PTS: 1 DIF: Webb's I OBJ: 3/1 STA: SC.A.2.3.2
13. ANS: F, atomic number
PTS: 1 DIF: Webb's I OBJ: 3/1 STA: SC.A.2.3.2
14. ANS: T PTS: 1 DIF: Webb's I
OBJ: 5/2
15. ANS: F, protons
PTS: 1 DIF: Webb's I OBJ: 3/1 STA: SC.A.2.3.2
16. ANS: F, less
PTS: 1 DIF: Webb's I OBJ: 3/1 STA: SC.A.2.3.2
MULTIPLE CHOICE
17. ANS: B PTS: 1 DIF: Webb's II STA: SC.H.1.3.1
18. ANS: D PTS: 1 DIF: Webb's I STA: SC.A.1.3.1
19. ANS: C PTS: 1 DIF: Webb's I STA: SC.H.1.3.1
20. ANS: C PTS: 1 DIF: Webb's I STA: SC.H.1.3.1 SC.A.2.3.2
21. ANS: B PTS: 1 DIF: Webb's II
STA: SC.H.1.3.1 SC.H.1.3.6 SC.H.3.3.5
22. ANS: D PTS: 1 DIF: Webb's I STA: SC.A.2.3.2
23. ANS: A PTS: 1 DIF: Webb's I STA: SC.A.2.3.2
24. ANS: D PTS: 1 DIF: Webb's II STA: SC.A.2.3.2
25. ANS: B PTS: 1 DIF: Webb's II STA: SC.A.2.3.2
26. ANS: C PTS: 1 DIF: Webb's II STA: SC.A.2.3.2 SC.D.1.3.5
27. ANS: C PTS: 1 DIF: Webb's II STA: SC.A.2.3.2 SC.D.1.3.5
28. ANS: C PTS: 1 DIF: Webb's I
29. ANS: A PTS: 1 DIF: Webb's II STA: SC.A.1.3.1
30. ANS: C PTS: 1 DIF: Webb's I OBJ: 3/1
STA: SC.A.2.3.2
31. ANS: B PTS: 1 DIF: Webb's I OBJ: 3/1
32. ANS: A PTS: 1 DIF: Webb's I OBJ: 5/2
STA: SC.A.2.3.2
33. ANS: D PTS: 1 DIF: Webb's I OBJ: 5/2
34. ANS: B PTS: 1 DIF: Webb's I OBJ: 3/1
STA: SC.A.2.3.2
35. ANS: C PTS: 1 DIF: Webb's I OBJ: 2/1
STA: SC.H.1.3.1 SC.H.1.3.6
36. ANS: B PTS: 1 DIF: Webb's I OBJ: 2/1
STA: SC.H.1.3.1 SC.H.1.3.6
37. ANS: C PTS: 1 DIF: Webb's I OBJ: 2/1
STA: SC.H.1.3.1 SC.H.1.3.6
38. ANS: D PTS: 1 DIF: Webb's II OBJ: 1/1
STA: SC.A.2.3.1 SC.A.2.3.2
39. ANS: A PTS: 1 DIF: Webb's I OBJ: 5/2
STA: SC.A.2.3.2
40. ANS: D PTS: 1 DIF: Webb's I OBJ: 5/2
STA: SC.A.2.3.2
41. ANS: A PTS: 1 DIF: Webb's I OBJ: 1/1
STA: SC.H.1.3.1 SC.H.1.3.6
42. ANS: D PTS: 1 DIF: Webb's I OBJ: 3/1
STA: SC.A.2.3.2
43. ANS: B PTS: 1 DIF: Webb's I OBJ: 5/2
44. ANS: B PTS: 1 DIF: Webb's I OBJ: 6/2
45. ANS: B PTS: 1
46. ANS: C PTS: 1
47. ANS: A PTS: 1
48. ANS: A PTS: 1
49. ANS: D PTS: 1
50. ANS: D PTS: 1
51. ANS: B PTS: 1
52. ANS: C PTS: 1
53. ANS: A PTS: 1
54. ANS: D PTS: 1
55. ANS: C PTS: 1
56. ANS: C PTS: 1
57. ANS: B PTS: 1
58. ANS: A PTS: 1
59. ANS: D PTS: 1
60. ANS: D PTS: 1
61. ANS: A PTS: 1
COMPLETION
62. ANS: nucleus
PTS: 1 DIF: Webb's I OBJ: 3/1 STA: SC.A.2.3.2
63. ANS: radioactive
PTS: 1 DIF: Webb's I OBJ: 4/1 STA: SC.A.2.3.2
64. ANS: beta particles
PTS: 1 DIF: Webb's I OBJ: 4/1 STA: SC.A.2.3.2
65. ANS: electron
PTS: 1 DIF: Webb's I OBJ: 3/1 STA: SC.A.2.3.2
66. ANS: cathode-ray
PTS: 1 DIF: Webb's I OBJ: 1/1 STA: SC.H.1.3.6
67. ANS: anode
PTS: 1 DIF: Webb's I OBJ: 1/1
68. ANS: electron cloud
PTS: 1 DIF: Webb's I OBJ: 3/1 STA: SC.A.2.3.2
69. ANS: isotopes
PTS: 1 DIF: Webb's I OBJ: 5/2 STA: SC.A.2.3.2
70. ANS: chemistry
PTS: 1
71. ANS: atoms
PTS: 1
72. ANS: anode
PTS: 1
73. ANS: cathode
PTS: 1
74. ANS: sphere
PTS: 1
75. ANS: random
PTS: 1
76. ANS: tracer elements
PTS: 1
77. ANS: atom
PTS: 1
78. ANS: atom
PTS: 1
79. ANS: cathode rays
PTS: 1
80. ANS: neutron
PTS: 1
81. ANS: equal to
PTS: 1
82. ANS: protons
PTS: 1
83. ANS: subtract the atomic number
PTS: 1
84. ANS: 1
PTS: 1
MATCHING
85. ANS: D PTS: 1 DIF: Webb's I OBJ: 6/2
86. ANS: A PTS: 1 DIF: Webb's I OBJ: 6/2
87. ANS: C PTS: 1 DIF: Webb's I OBJ: 6/2
88. ANS: B PTS: 1 DIF: Webb's I OBJ: 6/2
89. ANS: D PTS: 1 DIF: Webb's I OBJ: 2/1
STA: SC.A.2.3.2
90. ANS: B PTS: 1 DIF: Webb's I OBJ: 2/1
STA: SC.A.2.3.2
91. ANS: A PTS: 1 DIF: Webb's I OBJ: 1/1
STA: SC.A.2.3.1 SC.A.2.3.2
92. ANS: C PTS: 1 DIF: Webb's I OBJ: 1/1
STA: SC.A.2.3.1 SC.A.2.3.2
93. ANS: D PTS: 1
94. ANS: G PTS: 1
95. ANS: L PTS: 1
96. ANS: A PTS: 1
97. ANS: F PTS: 1
98. ANS: C PTS: 1
99. ANS: I PTS: 1
100. ANS: B PTS: 1
101. ANS: N PTS: 1
102. ANS: M PTS: 1
103. ANS: J PTS: 1
104. ANS: K PTS: 1
105. ANS: E PTS: 1
106. ANS: H PTS: 1
SHORT ANSWER
107. ANS:
The theory accounts for recent research that explains the unpredictable nature of electrons. The behavior of electrons is more comparable to that of waves than of particles. Electrons are also more likely to be found close to the nucleus because they are attracted to the positive charges of the protons. The electrons in the region surrounding the nucleus create a cloud-like appearance, which explains the name “electron cloud model.”
PTS: 1 DIF: Webb's II STA: SC.A.2.3.2 SC.H.1.3.1
108. ANS:
Part A Answers will vary, but may include the idea that scientific theories often build on each other over time. For example, one scientist may make discoveries about protons, enabling another group of scientists to do further research. Further research may uncover information about neutrons or other related information. This helps advance science and human culture by providing people with more general knowledge about life.
Part B Further exploration about atoms and atomic theories enables general scientific knowledge to increase. It also allows for possible cures for diseases and can save many lives.
PTS: 1 DIF: Webb's III STA: SC.H.1.3.6 SC.H.3.3.5
109. ANS:
Thomson used magnetic fields to detect charged particles in his cathode-ray tube. Because neutrons have no charge, the cathode-ray tube did not detect them.
PTS: 1 DIF: Webb's II OBJ: 1/1 STA: SC.H.1.3.1 SC.H.1.3.6
110. ANS:
A small quantity of the isotope would not decay quickly enough to produce the desired effect, if the isotope were absorbed into body tissues, the patient would be exposed to a prolonged and most likely damaging, dose of radiation.
PTS: 1 DIF: Webb's II OBJ: 6/2 STA: SC.A.2.3.3
111. ANS:
Beta particles 1) are emitted from the atom during radioactive decay, 2) originate in the nucleus when a neutron splits into a proton and electron, and 3) have higher energies than ordinary electrons.
PTS: 1 DIF: Webb's II OBJ: 5/2 STA: SC.A.2.3.2
112. ANS:
All atoms of an element are not identical. Many elements have more than one isotope. Although each atom of an element has the same number of protons, the numbers of neutrons in the atom's nucleus can vary.
PTS: 1 DIF: Webb's II OBJ: 2/1
STA: SC.A.2.3.2 SC.H.1.3.1 SC.H.1.3.6
113. ANS:
Dalton’s model was based on scientific research and open to challenge by further studies. The Greeks used logic, but they did not do experiments. Dalton also added the idea of different atoms for different elements.
PTS: 1 DIF: Webb's II OBJ: 2/1 STA: SC.H.1.3.1 SC.H.1.3.6
114. ANS:
An alpha particle consists of two protons and two neutrons, the same four particles as in a helium-4 nucleus (mass number 4 – atomic number 2).
PTS: 1 DIF: Webb's II OBJ: 5/2 STA: SC.A.2.3.2
115. ANS:
The paths of beta particles that passed near the nucleus would have been deflected in a different direction because of the force of attraction between the electrons and protons.
PTS: 1 DIF: Webb's II OBJ: 1/1 STA: SC.A.2.3.2
116. ANS:
No, carbon-14 can be used to date objects that were once alive, not objects like stone that were never alive. An organism had to absorb carbon-14 as a natural part of metabolism so that the decay process could begin when it died.
PTS: 1 DIF: Webb's II OBJ: 5/2
117. ANS:
The stream of particles are emitted by the cathode. The high-voltage electrical source supplies the energy for their release.
PTS: 1 DIF: Webb's II OBJ: 1/1 STA: SC.A.2.3.1
118. ANS:
Protons and neutrons in the nucleus account for almost all the mass of an atom. The electrons are almost without mass and perhaps can be explained as waves rather than particles.
PTS: 1 DIF: Webb's II OBJ: 3/1 STA: SC.A.2.3.2
119. ANS:
The scientist would need to rely on the difference in mass.
PTS: 1 DIF: Webb's II OBJ: 5/2
120. ANS:
The iodine-131 would show the larger initial decay because it has a much shorter half-life. The decay of iodine-131 would drop off dramatically during the week; there would be no noticeable change in decay for the carbon-14 sample.
PTS: 1 DIF: Webb's II OBJ: 6/2
121. ANS:
Theoretically, an isotope with a half-life of 400 years should provide enough alpha particles to allow the smoke detector to work for many more years. However, the sample of americium-241 in the detector may be so small that the number of alpha particles emitted drops below the needed level. Also, the reliability of other parts in the detector may be limited to ten years. The smoke detector should be replaced.
PTS: 1 DIF: Webb's II OBJ: 6/2
122. ANS:
Technetium and promethium have no stable isotopes. These two elements could have existed long ago, but any deposits of these elements have long since decayed.
PTS: 1 DIF: Webb's II OBJ: 5/2
123. ANS:
They based their theories on the observed behavior of atoms and of subatomic particles. For example, they couldn’t see an electron, but they could observe behavior of electrons in a cathode-ray tube. As they learned more about the behavior, they modified their theories.
PTS: 1 DIF: Webb's II OBJ: 2/1 STA: SC.H.1.3.1 SC.H.1.3.3
124. ANS:
Find a radioactive isotope of an element that is commonly found in rocks. The isotope would need to have a long half-life.
PTS: 1 DIF: Webb's II OBJ: 6/2
125. ANS:
Students may compare the Sun and the planets to the nucleus and electrons. The gravitational attraction between the Sun and planets can be compared to the attraction between electrons and protons in the nucleus. There is a lot of empty space in both systems. Unlike electrons, the planets are not identical. In contrast to the electron cloud, the location of the planets in relation to the Sun is definite. Electrons are likely to be close to the nucleus, but they could be anywhere.
PTS: 1 DIF: Webb's III OBJ: 3/1 STA: SC.A.2.3.2 SC.E.1.3.1
126. ANS:
Number of Subatomic Particles in Selected Isotopes
Isotope
Number of protons
Number of neutrons
Number of electrons
magnesium-24
12
12
12
magnesium-26
12
14
12
chlorine-35
17
18
17
chlorine-37
17
20
17
PTS: 1 DIF: Webb's II OBJ: 5/2 STA: SC.A.2.3.2
127. ANS:
Students’ models will probably focus on the large number of atoms and their possible arrangements. One possible analogy could use a chain link fence. With a single layer of fencing, the holes in the fence are obvious and easy to penetrate. With multiple layers placed one on top of the other, the structure becomes more solid and a path through the layers much less direct.
PTS: 1 DIF: Webb's III OBJ: 3/1 STA: SC.A.2.3.2
128. ANS:
D, E, A, B, C
PTS: 1 DIF: Webb's II OBJ: 2/1 STA: SC.H.1.3.6
129. ANS:
PTS: 1
130. ANS:
a. 6, 6
b. 1, 1
c. 12, 11
d. 6, 14
e. 18, 17
f. 12, 24
g. 9, 19
PTS: 1
131. ANS:
Atom a and atom d are isotopes. They have the same atomic number, or number of protons, but different mass numbers because the number of neutrons is different.
PTS: 1
132. ANS:
Atom c could be the “before” of an alpha ejection, and atom g could be the “after.”
PTS: 1
133. ANS:
Atom b, which has one proton and no neutrons, could not possibly emit an alpha particle, which consists of two protons and two neutrons.
PTS: 1
134. ANS:
Answers will vary slightly. Topics should indicate that neutrons, protons, and electrons are particles within atoms.
PTS: 1
135. ANS:
Answers will vary slightly. Topics should indicate uses of radioactive isotopes.
PTS: 1
136. ANS:
number of neutrons = mass number – atomic number
53 – 26 = 27
PTS: 1
137. ANS:
The number of neutrons in an atom, including isotopes of the same element, can be calculated by subtracting the atomic number from the mass number.
For carbon-12: number of neutrons = 12 – 6 = 6
For carbon-13: number of neutrons = 13 – 6 = 7
For carbon-14: number of neutrons = 14 – 6 = 8
PTS: 1
138. ANS:
PTS: 1
PROBLEM
139. ANS:
2 days
PTS: 1 DIF: Webb's II OBJ: 5/2
140. ANS:
0.155 g; 0.0388 g
PTS: 1 DIF: Webb's II OBJ: 5/2
141. ANS:
atomic number = 90; mass number = 231
PTS: 1 DIF: Webb's II OBJ: 5/2 STA: SC.A.2.3.2
142. ANS:
atomic number = 91; mass number = 231
PTS: 1 DIF: Webb's II OBJ: 4/1 STA: SC.A.2.3.2
ESSAY
143. ANS:
Americium-241 undergoes transmutation to neptunium by ejecting an alpha particle. The air in a smoke detector can conduct electricity because of the presence of the alpha particles. As long as the electric current flows, the smoke detector stays silent. If smoke enters the detector, the current is interrupted and the alarm sounds.
PTS: 1
7th Grade- Chapter 2 Online Review
7th Grade - Chapter 2 ONLINE REVIEW
Modified True/False
Indicate whether the statement is true or false. If false, change the identified word or phrase to make the statement true.
____ 1. The ability to burn is an example of a physical property. _________________________
____ 2. The state of matter is an example of a physical property. _________________________
____ 3. Ice, liquid water, and water vapor are the three states of water. _________________________
____ 4. The odor of a substance is an example of a physical property. _________________________
____ 5. Burning wood is an example of physical change. _________________________
____ 6. Physical changes are difficult or impossible to reverse. _________________________
____ 7. Sugar dissolved in tea and sugar in a bowl are not the same substance. _________________________
____ 8. The cracks that form in a sidewalk during winter are the result of a physical change. _________________________
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____ 9. When Genevieve smells a flower, she is showing an example of which kind of property of matter?
a.
chemical
b.
deposition
c.
physical
d.
vaporization
____ 10. Which state of matter do milk, juice, and vegetable oil represent?
a.
chemical
b.
gas
c.
liquid
d.
solid
____ 11. Which physical property of matter does NOT depend on the size of an object?
a.
density
b.
mass
c.
volume
d.
weight
____ 12. On a sunny winter day, Richard sees that the snow on the ground is beginning to melt. Which can he conclude about the temperature that day?
a.
The temperature was cold enough to turn a liquid into a solid.
b.
The weight of the snow was a factor in the increase in temperature.
c.
The temperature was warm enough to reach the melting point for snow.
d.
The density of the snow was a factor in the increase in temperature.
____ 13. If the mass of an object is 10 and its volume is 5, what is its density?
a.
1
b.
1.2
c.
2
d.
3
____ 14. When Marianne burns a log in the fireplace, which kind of property of matter is she demonstrating?
a.
chemical
b.
gas
c.
physical
d.
solubility
____ 15. Paul is looking around in his environment and observing the kinds of change that occur every day. He makes this chart of examples of change.
Which kinds of change do his examples represent?
a.
change in composition
b.
change in mass
c.
chemical change
d.
physical change
____ 16. What is the process called when a liquid changes into a gas?
a.
condensation
b.
deposition
c.
sublimation
d.
vaporization
____ 17. An old nail sometimes develops a reddish appearance called rust. Which term describes this change?
a.
chemical
b.
dissolving
c.
physical
d.
tarnish
____ 18. Rachel is finding that chemical changes occur in many different ways.
What could you conclude about the chemical changes listed in her chart?
a.
Chemical changes do not form new substances.
b.
During a chemical change, a substance absorbs energy.
c.
Energy is released during a chemical change.
d.
The formation of gas is due to a chemical change.
____ 19. Which type of change does a strong odor in rotting food indicate?
a.
change in solubility
b.
change in sublimation
c.
chemical change
d.
physical change
____ 20. What scientific law explains that the total mass of matter is the same before and after a physical change?
a.
Law of Conservation of Gases
b.
Law of Conservation of Mass
c.
Law of Conservation of Matter
d.
Law of Conservation of Weight
____ 21. People in Karen’s community recycle materials such as plastics, glass, and aluminum. Which is the BEST explanation for the reason for recycling?
a.
Household waste products are useless and cannot be reused.
b.
Recycling costs more than throwing materials into garbage dumps.
c.
Recycling forces people to separate their garbage and think about what they use.
d.
Waste products can be turned into new products using chemical and physical changes.
____ 22. The measurement of an object's mass is a ____.
a.
physical change
c.
chemical change
b.
physical property
d.
chemical property
____ 23. The ability of an apple to change color when exposed to air is a ____.
a.
physical property
c.
physical change
b.
chemical property
d.
chemical change
____ 24. The ability of a pond to freeze over in winter is a ____.
a.
physical property
c.
physical change
b.
chemical property
d.
chemical change
____ 25. Which of the following is NOT a possible sign of a chemical change?
a.
a change in state
c.
the release of a gas
b.
a change in color
d.
the release of energy
____ 26. Which of the following is NOT a possible sign of a physical change?
a.
a change in appearance
c.
the release of energy
b.
a change in volume
d.
a change in color
____ 27. When a newspaper is left in direct sunlight for a few days, the paper begins to turn yellow. The yellow color is evidence of a ____.
a.
physical property
c.
physical change
b.
chemical property
d.
chemical change
____ 28. Three examples of physical change are ____.
a.
boiling water, a nail rusting, a melting candle
b.
a pond freezing, breaking glass, a burning candle
c.
melting ice, mowing the lawn, carving a statue
d.
applying lipstick, making lemonade, baking bread
____ 29. When a chunk of dry ice is at room temperature, a cloud of carbon dioxide vapor forms. The carbon dioxide is changing from a ____.
a.
solid to a liquid
c.
liquid to plasma
b.
solid to a gas
d.
liquid to a gas
____ 30. Which of these is not a physical property of matter?
a.
density
c.
ability to burn
b.
mass
d.
texture
____ 31. An example of physical change involving more than one substance is ____.
a.
evaporating
c.
burning
b.
rusting
d.
dissolving
____ 32. An example of a change of state is ____.
a.
evaporating
c.
burning
b.
rusting
d.
dissolving
____ 33. Which of the following shows a behavioral property?
a.
peeling a banana
c.
snow melting in the Sun
b.
iron attracted to a lodestone
d.
hammer hitting a nail
____ 34. The ____ is an example of a chemical change.
a.
melting of chocolate
c.
salting of food
b.
freezing of water
d.
burning of paper
____ 35. Which of the following is an example of a chemical change?
a.
evaporating
c.
burning
b.
melting
d.
sublimation
____ 36. Which of these indicates that a chemical change has taken place?
a.
change from a liquid to a gas
c.
release of heat energy
b.
change in shape
d.
dissolving of a solid
____ 37. The density of a material is ____.
a.
how much the material weighs
b.
the mass of a unit volume of the material
c.
how much space the material takes up
d.
whether or not the material floats in a liquid
____ 38. The process of a liquid changing into a gas is called ____.
a.
sublimation
c.
vaporization
b.
condensation
d.
deposition
____ 39. The process of a gas changing into a liquid is called ____.
a.
sublimation
c.
vaporization
b.
condensation
d.
deposition
____ 40. The process of a solid changing directly into a gas, without ever becoming a liquid is called ____.
a.
sublimation
c.
vaporization
b.
condensation
d.
deposition
____ 41. The process in which a gas changes directly into a solid, without ever becoming a liquid is called ____.
a.
sublimation
c.
vaporization
b.
condensation
d.
deposition
____ 42. An object’s odor is a ____.
a.
physical property
c.
physical change
b.
chemical property
d.
chemical change
____ 43. A change in an object’s odor is the result of a ____.
a.
physical property
c.
physical change
b.
chemical property
d.
chemical change
____ 44. The precipitation of a solid can indicate a ____.
a.
physical property
c.
physical change
b.
chemical property
d.
chemical change
Completion
Complete each statement.
45. Photosynthesis in plants is an example of a ____________________ change.
46. The color of a material is an example of a ____________________ property.
47. The main difference between physical and chemical changes is that ____________________ changes are not reversible.
48. The evaporation of water is an example of a change in ____________________.
Unscramble the letters to form the correct word for each definition.
49. hacclime preptory: allows a substance to change to a new substance ____________________
50. malceich hagcen: original material is transformed into a new material ____________________
51. aeioocnnrstv fo sams: total mass is the same before and after a physical or chemical change ____________________
52. chyplais gnache: any alteration in size, shape, or form of matter ____________________
53. tendisy: relates an object’s mass to the amount of space it takes up ____________________
54. saphicly toppyrer: most of these characteristics can be observed with the senses ____________________
55. liigbon tnpoi: temperature at which a liquid turns into a gas ____________________
56. vhaiebro: how something acts ____________________
57. ulmove: how much space an object takes up ____________________
58. mtlgnei iotpn: temperature at which a solid turns into a liquid ____________________
59. ttsae: solid, liquid or gas ____________________
60. aaaceenrpp: properties you detect with your senses ____________________
61. Shape, color, and texture are examples of ____________________.
62. You can tell a(n) ____________________ has occurred when energy is taken in or given off.
63. The rusting of metal is an example of a(n) ____________________ change.
64. A change of ____________________ is an example of a physical change.
65. Milk and gasoline are examples of the ____________________ of matter.
66. Mass and volume depend on the ____________________ of matter.
67. ____________________ measures how much mass is in a given volume.
68. You can use a table to find the ____________________ point of most substances.
69. The fact that something is magnetic can be determined by watching its ____________________.
70. A(n) ____________________ can only be determined by changing a substance.
71. ____________________ is when a gas changes into a solid.
72. ____________________ can indicate physical or chemical changes depending on the cause of the change.
73. Energy is ____________________ in a chemical change.
74. Formation of a(n) ____________________ is an indication of chemical change.
75. The total ____________________ of the matter is the same before and after a physical or chemical change. This is the ______________________________.
Classify the following changes by writing physical or chemical.
76. tearing paper ____________________
77. wax melting ____________________
78. wood burning ____________________
79. peeling a potato ____________________
80. iron rusting ____________________
81. sanding wood ____________________
82. milk souring ____________________
83. silver tarnishing ____________________
Matching
Match the type of property with the example.
a.
physical property
b.
chemical property
____ 84. a box measures 4 cm by 3 cm by 8 cm
____ 85. the liquid burned easily
____ 86. the muffins baked for 20 minutes until done
____ 87. the dessert tasted rich and chocolatey
Match the signs of chemical change with the examples of chemical change.
a.
the formation of a precipitate
c.
release of light and heat
b.
a change in color
d.
the formation of a gas
____ 88. burning wood in a fireplace
____ 89. antacid tablet in water
____ 90. solution of sodium nitrate is mixed with a solution of lead nitrate
____ 91. leaving peeled fruit on a kitchen counter
Match each item to the correct statement below.
a.
state
g.
physical change
b.
boiling point
h.
physical property
c.
chemical change
i.
behavior
d.
chemical property
j.
release of energy
e.
density
k.
mass
f.
color
l.
liquid
____ 92. an indication that a chemical change has taken place
____ 93. temperature at which liquid changes to gas
____ 94. a physical property of matter
____ 95. size, shape, or state of matter
____ 96. measure of how much of an object there is
____ 97. property that could be used to indicate physical or chemical change
____ 98. Melting is an example.
____ 99. The ability to burn is an example.
____ 100. liquid, gas, or solid
____ 101. how something acts
____ 102. a state of matter
____ 103. Rusting of iron is an example.
Short Answer
104.
Explain the difference between a physical and a chemical property.
105.
Why is the state of matter a physical property and not a chemical property?
106.
Why should you never taste anything in the laboratory unless your teacher tells you it's okay?
107.
How can you tell that fireworks exploded during a typical Fourth of July display don't all contain exactly the same ingredients?
108.
Describe five physical properties of a lemon, three that are constant for every lemon and two that can vary from lemon to lemon.
109.
Explain why the appearance of a gas is not always a sign of a chemical change.
110.
Sometimes people collect items such as eggshells, lawn clippings, and leaves into a compost heap in the backyard. The pile should be turned over once or twice a year to release heat that builds up in the center. What do you think is happening inside the compost pile?
111.
Explain how color can be classified as both a physical property and as one indication of a chemical change.
112.
Suppose someone goes to a salon to get his or her hair trimmed, bleached, and braided. Identify which of these processes involves a chemical change and a physical change. Explain your answers.
113.
What is the difference between a chemical change and a physical change?
114.
In the fall, you rake leaves into a pile, burn them, and spread the ashes back on the lawn as fertilizer. What are the chemical changes and what are the physical changes in this process?
115.
When yeast is added to bread dough, it produces carbon dioxide. The pressure of the gas causes the dough to expand. Explain how the rising of dough is an example of both a physical and a chemical change.
116.
Suppose a customer brings a gold bracelet to a jeweler and asks for it to be changed into a gold ring. What property will distinguish the ring from the bracelet? Will the changes required be physical or chemical? Explain your answer.
117.
Auto bodies have usually been made almost entirely from steel, and the main ingredient of steel is iron. However, on many cars, doors and fenders are made of plastic. What key advantage might plastic have over an iron-based material?
118.
Describe three items that you might prepare for breakfast that are changed chemically or physically during preparation.
119.
When a shiny penny turns dull, is the change physical or chemical?
120.
Explain why it is safe to eat table salt even though it is made from sodium, which can burn in water, and chlorine, which is a poisonous gas.
121.
Rock salt is used on winter roads to control icing. Cars become covered with salt from the road. However, salt on a car is not rock salt but powdered salt. Use your knowledge of physical and chemical changes to explain the change in the salt.
122.
Explain how water causes weathering in rocks.
123.
Identify the following properties of matter as size dependent or size independent: density, state, weight, color, volume, ability to attract a magnet, solubility, mass, melting/boiling point.
124.
Define the law of conservation of mass and explain how it relates to physical and chemical changes.
125. List some physical properties that are size dependent.
126. List some physical properties that are size independent.
Think of a piece of notebook paper as you answer the following questions.
127. List three ways you could change the physical properties of the piece of paper.
128. In what ways can you change its chemical properties?
129. Do you think most people cause physical or chemical changes to notebook paper? How?
130. Compare and contrast the changes a piece of paper undergoes when it is torn into tiny pieces and when it is burned.
131. Compare and contrast chemical and physical changes.
132. How does the formation of drops of water on the outside of a glass of iced tea indicate the presence of water vapor, an invisible gas, in the air surrounding the glass? What kind of change is involved in this process?
133. When does the color change in a leaf indicate physical change and when does it indicate chemical change?
134. In a mixture of iron filings and sulfur powder, the particles of each substance are clearly visible and a magnet can be used to separate the iron from the sulfur. After the mixture is heated strongly, neither substance is recognizable and the resulting product is not magnetic. Explain what happened.
135. What is the difference between dissolving sugar in water and making cookies with sugar in them?
136. Classify each of the following properties of sucrose as chemical or physical.
a. It has a melting point of 186°C.
b. It is white solid.
c. It decomposes above 200°C.
d. Its density is 1.58 g/cm3.
e. Its consumption produces 52 kJ of energy per teaspoon.
Essay
137.
Physical changes are sometimes easier to identify than chemical changes.
Part A Give an example of a chemical change that occurs seasonally in a tree.
Part B Explain the process of the chemical change.
138. Why is an object’s mass a size-dependent physical property while its density is a size-independent physical property?
139. Using what you know about chemical change and the law of conservation of mass, explain why you think many communities no longer allow residents to burn fallen leaves each autumn.
7th Grade - Chapter 2 ONLINE REVIEW
Answer Section
MODIFIED TRUE/FALSE
1. ANS: F, chemical
PTS: 1 DIF: Webb's I OBJ: 1/1 STA: SC.A.1.3.5
2. ANS: T PTS: 1 DIF: Webb's I
OBJ: 1/1 STA: SC.A.1.3.5
3. ANS: T PTS: 1 DIF: Webb's I
OBJ: 1/1 STA: SC.A.1.3.5
4. ANS: T PTS: 1 DIF: Webb's I
OBJ: 1/1 STA: SC.A.1.3.5
5. ANS: F, chemical
PTS: 1 DIF: Webb's I OBJ: 4/2 STA: SC.A.1.3.5
6. ANS: F, Chemical
PTS: 1 DIF: Webb's I OBJ: 4/2 STA: SC.A.1.3.5
7. ANS: F, are
PTS: 1 DIF: Webb's I OBJ: 3/2 STA: SC.A.1.3.5
8. ANS: T PTS: 1 DIF: Webb's I
OBJ: 3/2 STA: SC.A.1.3.5
MULTIPLE CHOICE
9. ANS: A PTS: 1 DIF: Webb's I STA: SC.A.1.3.1
10. ANS: C PTS: 1 DIF: Webb's I STA: SC.A.1.3.1
11. ANS: A PTS: 1 DIF: Webb's I STA: SC.A.1.3.1
12. ANS: C PTS: 1 DIF: Webb's II STA: SC.A.1.3.1 SC.A.1.3.5
13. ANS: C PTS: 1 DIF: Webb's II STA: SC.A.1.3.1
14. ANS: A PTS: 1 DIF: Webb's I STA: SC.A.1.3.1 SC.A.1.3.5
15. ANS: D PTS: 1 DIF: Webb's II STA: SC.A.1.3.5
16. ANS: D PTS: 1 DIF: Webb's I STA: SC.A.1.3.5
17. ANS: A PTS: 1 DIF: Webb's I STA: SC.A.1.3.5
18. ANS: C PTS: 1 DIF: Webb's II STA: SC.A.1.3.5
19. ANS: C PTS: 1 DIF: Webb's I STA: SC.A.1.3.5
20. ANS: B PTS: 1 DIF: Webb's I STA: SC.A.1.3.5
21. ANS: D PTS: 1 DIF: Webb's II STA: SC.A.1.3.5 SC.G.2.3.4
22. ANS: B PTS: 1 DIF: Webb's I OBJ: 1/1
STA: SC.A.1.3.2 SC.A.1.3.5
23. ANS: B PTS: 1 DIF: Webb's I OBJ: 1/1
STA: SC.A.1.3.5
24. ANS: A PTS: 1 DIF: Webb's I OBJ: 1/1
STA: SC.A.1.3.5
25. ANS: A PTS: 1 DIF: Webb's II OBJ: 4/2
STA: SC.A.1.3.5
26. ANS: C PTS: 1 DIF: Webb's II OBJ: 4/2
STA: SC.A.1.3.5
27. ANS: D PTS: 1 DIF: Webb's I OBJ: 3/2
STA: SC.A.1.3.5
28. ANS: C PTS: 1 DIF: Webb's I OBJ: 3/2
STA: SC.A.1.3.5
29. ANS: B PTS: 1 DIF: Webb's II OBJ: 3/2
STA: SC.A.1.3.5
30. ANS: C PTS: 1
31. ANS: D PTS: 1
32. ANS: A PTS: 1
33. ANS: B PTS: 1
34. ANS: D PTS: 1
35. ANS: C PTS: 1
36. ANS: C PTS: 1
37. ANS: B PTS: 1
38. ANS: C PTS: 1
39. ANS: B PTS: 1
40. ANS: A PTS: 1
41. ANS: D PTS: 1
42. ANS: A PTS: 1
43. ANS: D PTS: 1
44. ANS: D PTS: 1
COMPLETION
45. ANS: chemical
PTS: 1 DIF: Webb's I OBJ: 3/2 STA: SC.A.1.3.5
46. ANS: physical
PTS: 1 DIF: Webb's I OBJ: 1/1 STA: SC.A.1.3.5
47. ANS: chemical
PTS: 1 DIF: Webb's I OBJ: 4/2 STA: SC.A.1.3.5
48. ANS: state
PTS: 1 DIF: Webb's I OBJ: 3/2 STA: SC.A.1.3.5
49. ANS: chemical property
PTS: 1
50. ANS: chemical change
PTS: 1
51. ANS: conservation of mass
PTS: 1
52. ANS: physical change
PTS: 1
53. ANS: density
PTS: 1
54. ANS: physical property
PTS: 1
55. ANS: boiling point
PTS: 1
56. ANS: behavior
PTS: 1
57. ANS: volume
PTS: 1
58. ANS: melting point
PTS: 1
59. ANS: state
PTS: 1
60. ANS: appearance
PTS: 1
61. ANS: physical properties
PTS: 1
62. ANS: chemical change
PTS: 1
63. ANS: chemical
PTS: 1
64. ANS: state
PTS: 1
65. ANS: liquid state
PTS: 1
66. ANS: amount
PTS: 1
67. ANS: Density
PTS: 1
68. ANS:
melting
boiling
PTS: 1
69. ANS: behavior
PTS: 1
70. ANS: chemical property
PTS: 1
71. ANS: Deposition
PTS: 1
72. ANS: Color
PTS: 1
73. ANS:
gained
released
PTS: 1
74. ANS:
gas
solid
PTS: 1
75. ANS: mass, law of conservation of mass
PTS: 1
76. ANS: physical
PTS: 1
77. ANS: physical
PTS: 1
78. ANS: chemical
PTS: 1
79. ANS: physical
PTS: 1
80. ANS: chemical
PTS: 1
81. ANS: physical
PTS: 1
82. ANS: chemical
PTS: 1
83. ANS: chemical
PTS: 1
MATCHING
84. ANS: A PTS: 1 DIF: Webb's II OBJ: 1/1
STA: SC.A.1.3.5
85. ANS: B PTS: 1 DIF: Webb's II OBJ: 1/1
STA: SC.A.1.3.5
86. ANS: B PTS: 1 DIF: Webb's II OBJ: 1/1
STA: SC.A.1.3.5
87. ANS: A PTS: 1 DIF: Webb's II OBJ: 1/1
STA: SC.A.1.3.5
88. ANS: C PTS: 1 DIF: Webb's II OBJ: 3/2
STA: SC.A.1.3.5
89. ANS: D PTS: 1 DIF: Webb's II OBJ: 3/2
STA: SC.A.1.3.5
90. ANS: A PTS: 1 DIF: Webb's II OBJ: 3/2
STA: SC.A.1.3.5
91. ANS: B PTS: 1 DIF: Webb's II OBJ: 3/2
STA: SC.A.1.3.5
92. ANS: J PTS: 1
93. ANS: B PTS: 1
94. ANS: E PTS: 1
95. ANS: H PTS: 1
96. ANS: K PTS: 1
97. ANS: F PTS: 1
98. ANS: G PTS: 1
99. ANS: D PTS: 1
100. ANS: A PTS: 1
101. ANS: I PTS: 1
102. ANS: L PTS: 1
103. ANS: C PTS: 1
SHORT ANSWER
104. ANS:
A chemical property is a characteristic that cannot be observed without altering the substance observed. A physical property is a characteristic that a person can observe without changing the composition of that substance.
PTS: 1 DIF: Webb's II STA: SC.A.1.3.1
105. ANS:
Changing state does not change the identity of the matter. Water is still water whether it is ice, liquid, or vapor. Chemical properties can't be observed without changing the substance.
PTS: 1 DIF: Webb's II OBJ: 1/1 STA: SC.A.1.3.5
106. ANS:
There could be a poisonous residue on the glassware, or a chemical change may have occurred, causing something to become poisonous.
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.1 SC.A.1.3.5
107. ANS:
The starting materials must differ because the materials produced during the explosions have different colors.
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.5
108. ANS:
Constant: color, taste, texture of skin; not constant: size, shape
PTS: 1 DIF: Webb's II OBJ: 1/1 STA: SC.A.1.3.5
109. ANS:
A gas can be the result of a change of state, which is a physical change. The boiling of water produces water vapor; opening a carbonated beverage releases dissolved carbon dioxide.
PTS: 1 DIF: Webb's II OBJ: 4/2 STA: SC.A.1.3.4
110. ANS:
The material is decomposing, which is a chemical change; heat is the evidence of change.
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.5
111. ANS:
Color is a physical property because it can be observed without changing the substance, but when new substances form during a chemical change, there may be a change in color because the new substances will have a different set of physical properties.
PTS: 1 DIF: Webb's II OBJ: 4/2 STA: SC.A.1.3.5
112. ANS:
The trimming and braiding are physical changes because they are changes in size and shape. The bleaching is a chemical change because it produces a change in color.
PTS: 1 DIF: Webb's II OBJ: 4/2 STA: SC.A.1.3.5
113. ANS:
A chemical change changes the substance. A physical change doesn't affect the basics of the substance.
PTS: 1 DIF: Webb's II OBJ: 2/1 STA: SC.A.1.3.5
114. ANS:
Raking the leaves into a pile and spreading the ashes are physical changes. Burning the leaves and the ashes being broken down by the lawn for fertilizer are chemical changes.
PTS: 1 DIF: Webb's II OBJ: 4/2 STA: SC.A.1.3.5
115. ANS:
The carbon dioxide gas produced indicates that a chemical change has occurred. The change in volume as the dough rises is an example of a physical change.
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.5
116. ANS:
shape; physical; The solid bracelet must be heated until it melts, then liquid gold must be poured into a ring-shaped mold and allowed to harden. The new ring will still have the same composition as the bracelet.
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.5
117. ANS:
Plastic doesn't rust when exposed to the oxygen in air and water. (Also, the plastic rebounds from gentle impacts, and a car with less density is more fuel efficient.)
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.5
118. ANS:
Possible choices: physically changing a banana by peeling and slicing; physically changing water by heating; physically changing oranges to make juice; chemically changing bread by toasting; chemically changing eggs or meat by cooking.
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.5
119. ANS:
chemical; the metal in the penny has combined with oxygen in the air
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.5
120. ANS:
The product of a chemical change can have very different physical and chemical properties from the original materials.
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.1 SC.A.1.3.5
121. ANS:
The rock salt dissolved in water from snow or rain. The water evaporated from the surface of the car leaving powdered salt, a physical change.
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.5
122. ANS:
Water can freeze and expand in the crevices of rocks, causing them to split into smaller pieces. Water can also dissolve materials from rocks.
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.1 SC.A.1.3.5
123. ANS:
size dependent: mass, weight, volume; size independent: density, melting/boiling point, solubility, ability to attract a magnet, state, color
PTS: 1 DIF: Webb's II OBJ: 1/1 STA: SC.A.1.3.1 SC.A.1.3.5
124. ANS:
The law of conservation of mass states that mass cannot be created or destroyed. This means that the mass of any substances present before a physical or chemical change is equal to the mass of the substances present after the change.
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.2 SC.A.1.3.5
125. ANS:
Answers may include mass, weight, volume.
PTS: 1
126. ANS:
Answers may include density, melting point, boiling point, solubility, ability to attract a magnet, state of matter, color.
PTS: 1
127. ANS:
Possible answers include: coloring the paper, crumpling the paper, tearing it, or dissolving it.
PTS: 1
128. ANS:
Burn it or dissolve it in acid.
PTS: 1
129. ANS:
Most people cause physical changes because they use notebook paper to take notes or write things on. Very few people burn notebook paper.
PTS: 1
130. ANS:
The tearing of paper is a physical change. The only changes in the paper caused by tearing are changes in size and shape. The burning of paper is a chemical change. During this change, paper is changed into ashes, smoke, and gases.
PTS: 1
131. ANS:
Both change the substance from what is first seen. Chemical changes are not easily reversed. Physical changes just change the observable parts of a substance, but the basic substance is unchanged.
PTS: 1
132. ANS:
The formation of the water drops indicates that water vapor in the air has condensed, or changed to a liquid, on the sides of the glass. Condensation is a physical change.
PTS: 1
133. ANS:
If the color change is caused by a reaction within the leaf, it is chemical. If it is caused by bird droppings or berry juice, it is physical.
PTS: 1
134. ANS:
Heating caused a chemical change to take place. The chemical properties of the new product have changed and a new substance has been formed.
PTS: 1
135. ANS:
Dissolving sugar in water is a physical change. Making cookies with sugar is a chemical change.
PTS: 1
136. ANS:
a. physical
b. physical
c. chemical
d. physical
e. chemical
PTS: 1
ESSAY
137. ANS:
Part A In the fall, the leaves of many trees begin to change color. This is a visible example of a chemical change that is occurring in the tree.
Part B In the fall, the chlorophyll in the tree’s leaves undergoes a chemical change into colorless chemicals. This allows different colors of pigment such as red and orange now to be seen.
PTS: 1 DIF: Webb's II STA: SC.A.1.3.5
138. ANS:
Mass, weight, and volume of an object are size dependent; they are greater or less, depending on the size of the object. Size-independent physical properties are the same, regardless of the paper’s size. Density, which is mass divided by volume, does not change with size.
PTS: 1
139. ANS:
Answers will vary. Look for answers that define chemical change and the law of conservation of mass and relate the mass of fallen leaves to an equal amount of particles that could pollute the air.
PTS: 1
Modified True/False
Indicate whether the statement is true or false. If false, change the identified word or phrase to make the statement true.
____ 1. The ability to burn is an example of a physical property. _________________________
____ 2. The state of matter is an example of a physical property. _________________________
____ 3. Ice, liquid water, and water vapor are the three states of water. _________________________
____ 4. The odor of a substance is an example of a physical property. _________________________
____ 5. Burning wood is an example of physical change. _________________________
____ 6. Physical changes are difficult or impossible to reverse. _________________________
____ 7. Sugar dissolved in tea and sugar in a bowl are not the same substance. _________________________
____ 8. The cracks that form in a sidewalk during winter are the result of a physical change. _________________________
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____ 9. When Genevieve smells a flower, she is showing an example of which kind of property of matter?
a.
chemical
b.
deposition
c.
physical
d.
vaporization
____ 10. Which state of matter do milk, juice, and vegetable oil represent?
a.
chemical
b.
gas
c.
liquid
d.
solid
____ 11. Which physical property of matter does NOT depend on the size of an object?
a.
density
b.
mass
c.
volume
d.
weight
____ 12. On a sunny winter day, Richard sees that the snow on the ground is beginning to melt. Which can he conclude about the temperature that day?
a.
The temperature was cold enough to turn a liquid into a solid.
b.
The weight of the snow was a factor in the increase in temperature.
c.
The temperature was warm enough to reach the melting point for snow.
d.
The density of the snow was a factor in the increase in temperature.
____ 13. If the mass of an object is 10 and its volume is 5, what is its density?
a.
1
b.
1.2
c.
2
d.
3
____ 14. When Marianne burns a log in the fireplace, which kind of property of matter is she demonstrating?
a.
chemical
b.
gas
c.
physical
d.
solubility
____ 15. Paul is looking around in his environment and observing the kinds of change that occur every day. He makes this chart of examples of change.
Which kinds of change do his examples represent?
a.
change in composition
b.
change in mass
c.
chemical change
d.
physical change
____ 16. What is the process called when a liquid changes into a gas?
a.
condensation
b.
deposition
c.
sublimation
d.
vaporization
____ 17. An old nail sometimes develops a reddish appearance called rust. Which term describes this change?
a.
chemical
b.
dissolving
c.
physical
d.
tarnish
____ 18. Rachel is finding that chemical changes occur in many different ways.
What could you conclude about the chemical changes listed in her chart?
a.
Chemical changes do not form new substances.
b.
During a chemical change, a substance absorbs energy.
c.
Energy is released during a chemical change.
d.
The formation of gas is due to a chemical change.
____ 19. Which type of change does a strong odor in rotting food indicate?
a.
change in solubility
b.
change in sublimation
c.
chemical change
d.
physical change
____ 20. What scientific law explains that the total mass of matter is the same before and after a physical change?
a.
Law of Conservation of Gases
b.
Law of Conservation of Mass
c.
Law of Conservation of Matter
d.
Law of Conservation of Weight
____ 21. People in Karen’s community recycle materials such as plastics, glass, and aluminum. Which is the BEST explanation for the reason for recycling?
a.
Household waste products are useless and cannot be reused.
b.
Recycling costs more than throwing materials into garbage dumps.
c.
Recycling forces people to separate their garbage and think about what they use.
d.
Waste products can be turned into new products using chemical and physical changes.
____ 22. The measurement of an object's mass is a ____.
a.
physical change
c.
chemical change
b.
physical property
d.
chemical property
____ 23. The ability of an apple to change color when exposed to air is a ____.
a.
physical property
c.
physical change
b.
chemical property
d.
chemical change
____ 24. The ability of a pond to freeze over in winter is a ____.
a.
physical property
c.
physical change
b.
chemical property
d.
chemical change
____ 25. Which of the following is NOT a possible sign of a chemical change?
a.
a change in state
c.
the release of a gas
b.
a change in color
d.
the release of energy
____ 26. Which of the following is NOT a possible sign of a physical change?
a.
a change in appearance
c.
the release of energy
b.
a change in volume
d.
a change in color
____ 27. When a newspaper is left in direct sunlight for a few days, the paper begins to turn yellow. The yellow color is evidence of a ____.
a.
physical property
c.
physical change
b.
chemical property
d.
chemical change
____ 28. Three examples of physical change are ____.
a.
boiling water, a nail rusting, a melting candle
b.
a pond freezing, breaking glass, a burning candle
c.
melting ice, mowing the lawn, carving a statue
d.
applying lipstick, making lemonade, baking bread
____ 29. When a chunk of dry ice is at room temperature, a cloud of carbon dioxide vapor forms. The carbon dioxide is changing from a ____.
a.
solid to a liquid
c.
liquid to plasma
b.
solid to a gas
d.
liquid to a gas
____ 30. Which of these is not a physical property of matter?
a.
density
c.
ability to burn
b.
mass
d.
texture
____ 31. An example of physical change involving more than one substance is ____.
a.
evaporating
c.
burning
b.
rusting
d.
dissolving
____ 32. An example of a change of state is ____.
a.
evaporating
c.
burning
b.
rusting
d.
dissolving
____ 33. Which of the following shows a behavioral property?
a.
peeling a banana
c.
snow melting in the Sun
b.
iron attracted to a lodestone
d.
hammer hitting a nail
____ 34. The ____ is an example of a chemical change.
a.
melting of chocolate
c.
salting of food
b.
freezing of water
d.
burning of paper
____ 35. Which of the following is an example of a chemical change?
a.
evaporating
c.
burning
b.
melting
d.
sublimation
____ 36. Which of these indicates that a chemical change has taken place?
a.
change from a liquid to a gas
c.
release of heat energy
b.
change in shape
d.
dissolving of a solid
____ 37. The density of a material is ____.
a.
how much the material weighs
b.
the mass of a unit volume of the material
c.
how much space the material takes up
d.
whether or not the material floats in a liquid
____ 38. The process of a liquid changing into a gas is called ____.
a.
sublimation
c.
vaporization
b.
condensation
d.
deposition
____ 39. The process of a gas changing into a liquid is called ____.
a.
sublimation
c.
vaporization
b.
condensation
d.
deposition
____ 40. The process of a solid changing directly into a gas, without ever becoming a liquid is called ____.
a.
sublimation
c.
vaporization
b.
condensation
d.
deposition
____ 41. The process in which a gas changes directly into a solid, without ever becoming a liquid is called ____.
a.
sublimation
c.
vaporization
b.
condensation
d.
deposition
____ 42. An object’s odor is a ____.
a.
physical property
c.
physical change
b.
chemical property
d.
chemical change
____ 43. A change in an object’s odor is the result of a ____.
a.
physical property
c.
physical change
b.
chemical property
d.
chemical change
____ 44. The precipitation of a solid can indicate a ____.
a.
physical property
c.
physical change
b.
chemical property
d.
chemical change
Completion
Complete each statement.
45. Photosynthesis in plants is an example of a ____________________ change.
46. The color of a material is an example of a ____________________ property.
47. The main difference between physical and chemical changes is that ____________________ changes are not reversible.
48. The evaporation of water is an example of a change in ____________________.
Unscramble the letters to form the correct word for each definition.
49. hacclime preptory: allows a substance to change to a new substance ____________________
50. malceich hagcen: original material is transformed into a new material ____________________
51. aeioocnnrstv fo sams: total mass is the same before and after a physical or chemical change ____________________
52. chyplais gnache: any alteration in size, shape, or form of matter ____________________
53. tendisy: relates an object’s mass to the amount of space it takes up ____________________
54. saphicly toppyrer: most of these characteristics can be observed with the senses ____________________
55. liigbon tnpoi: temperature at which a liquid turns into a gas ____________________
56. vhaiebro: how something acts ____________________
57. ulmove: how much space an object takes up ____________________
58. mtlgnei iotpn: temperature at which a solid turns into a liquid ____________________
59. ttsae: solid, liquid or gas ____________________
60. aaaceenrpp: properties you detect with your senses ____________________
61. Shape, color, and texture are examples of ____________________.
62. You can tell a(n) ____________________ has occurred when energy is taken in or given off.
63. The rusting of metal is an example of a(n) ____________________ change.
64. A change of ____________________ is an example of a physical change.
65. Milk and gasoline are examples of the ____________________ of matter.
66. Mass and volume depend on the ____________________ of matter.
67. ____________________ measures how much mass is in a given volume.
68. You can use a table to find the ____________________ point of most substances.
69. The fact that something is magnetic can be determined by watching its ____________________.
70. A(n) ____________________ can only be determined by changing a substance.
71. ____________________ is when a gas changes into a solid.
72. ____________________ can indicate physical or chemical changes depending on the cause of the change.
73. Energy is ____________________ in a chemical change.
74. Formation of a(n) ____________________ is an indication of chemical change.
75. The total ____________________ of the matter is the same before and after a physical or chemical change. This is the ______________________________.
Classify the following changes by writing physical or chemical.
76. tearing paper ____________________
77. wax melting ____________________
78. wood burning ____________________
79. peeling a potato ____________________
80. iron rusting ____________________
81. sanding wood ____________________
82. milk souring ____________________
83. silver tarnishing ____________________
Matching
Match the type of property with the example.
a.
physical property
b.
chemical property
____ 84. a box measures 4 cm by 3 cm by 8 cm
____ 85. the liquid burned easily
____ 86. the muffins baked for 20 minutes until done
____ 87. the dessert tasted rich and chocolatey
Match the signs of chemical change with the examples of chemical change.
a.
the formation of a precipitate
c.
release of light and heat
b.
a change in color
d.
the formation of a gas
____ 88. burning wood in a fireplace
____ 89. antacid tablet in water
____ 90. solution of sodium nitrate is mixed with a solution of lead nitrate
____ 91. leaving peeled fruit on a kitchen counter
Match each item to the correct statement below.
a.
state
g.
physical change
b.
boiling point
h.
physical property
c.
chemical change
i.
behavior
d.
chemical property
j.
release of energy
e.
density
k.
mass
f.
color
l.
liquid
____ 92. an indication that a chemical change has taken place
____ 93. temperature at which liquid changes to gas
____ 94. a physical property of matter
____ 95. size, shape, or state of matter
____ 96. measure of how much of an object there is
____ 97. property that could be used to indicate physical or chemical change
____ 98. Melting is an example.
____ 99. The ability to burn is an example.
____ 100. liquid, gas, or solid
____ 101. how something acts
____ 102. a state of matter
____ 103. Rusting of iron is an example.
Short Answer
104.
Explain the difference between a physical and a chemical property.
105.
Why is the state of matter a physical property and not a chemical property?
106.
Why should you never taste anything in the laboratory unless your teacher tells you it's okay?
107.
How can you tell that fireworks exploded during a typical Fourth of July display don't all contain exactly the same ingredients?
108.
Describe five physical properties of a lemon, three that are constant for every lemon and two that can vary from lemon to lemon.
109.
Explain why the appearance of a gas is not always a sign of a chemical change.
110.
Sometimes people collect items such as eggshells, lawn clippings, and leaves into a compost heap in the backyard. The pile should be turned over once or twice a year to release heat that builds up in the center. What do you think is happening inside the compost pile?
111.
Explain how color can be classified as both a physical property and as one indication of a chemical change.
112.
Suppose someone goes to a salon to get his or her hair trimmed, bleached, and braided. Identify which of these processes involves a chemical change and a physical change. Explain your answers.
113.
What is the difference between a chemical change and a physical change?
114.
In the fall, you rake leaves into a pile, burn them, and spread the ashes back on the lawn as fertilizer. What are the chemical changes and what are the physical changes in this process?
115.
When yeast is added to bread dough, it produces carbon dioxide. The pressure of the gas causes the dough to expand. Explain how the rising of dough is an example of both a physical and a chemical change.
116.
Suppose a customer brings a gold bracelet to a jeweler and asks for it to be changed into a gold ring. What property will distinguish the ring from the bracelet? Will the changes required be physical or chemical? Explain your answer.
117.
Auto bodies have usually been made almost entirely from steel, and the main ingredient of steel is iron. However, on many cars, doors and fenders are made of plastic. What key advantage might plastic have over an iron-based material?
118.
Describe three items that you might prepare for breakfast that are changed chemically or physically during preparation.
119.
When a shiny penny turns dull, is the change physical or chemical?
120.
Explain why it is safe to eat table salt even though it is made from sodium, which can burn in water, and chlorine, which is a poisonous gas.
121.
Rock salt is used on winter roads to control icing. Cars become covered with salt from the road. However, salt on a car is not rock salt but powdered salt. Use your knowledge of physical and chemical changes to explain the change in the salt.
122.
Explain how water causes weathering in rocks.
123.
Identify the following properties of matter as size dependent or size independent: density, state, weight, color, volume, ability to attract a magnet, solubility, mass, melting/boiling point.
124.
Define the law of conservation of mass and explain how it relates to physical and chemical changes.
125. List some physical properties that are size dependent.
126. List some physical properties that are size independent.
Think of a piece of notebook paper as you answer the following questions.
127. List three ways you could change the physical properties of the piece of paper.
128. In what ways can you change its chemical properties?
129. Do you think most people cause physical or chemical changes to notebook paper? How?
130. Compare and contrast the changes a piece of paper undergoes when it is torn into tiny pieces and when it is burned.
131. Compare and contrast chemical and physical changes.
132. How does the formation of drops of water on the outside of a glass of iced tea indicate the presence of water vapor, an invisible gas, in the air surrounding the glass? What kind of change is involved in this process?
133. When does the color change in a leaf indicate physical change and when does it indicate chemical change?
134. In a mixture of iron filings and sulfur powder, the particles of each substance are clearly visible and a magnet can be used to separate the iron from the sulfur. After the mixture is heated strongly, neither substance is recognizable and the resulting product is not magnetic. Explain what happened.
135. What is the difference between dissolving sugar in water and making cookies with sugar in them?
136. Classify each of the following properties of sucrose as chemical or physical.
a. It has a melting point of 186°C.
b. It is white solid.
c. It decomposes above 200°C.
d. Its density is 1.58 g/cm3.
e. Its consumption produces 52 kJ of energy per teaspoon.
Essay
137.
Physical changes are sometimes easier to identify than chemical changes.
Part A Give an example of a chemical change that occurs seasonally in a tree.
Part B Explain the process of the chemical change.
138. Why is an object’s mass a size-dependent physical property while its density is a size-independent physical property?
139. Using what you know about chemical change and the law of conservation of mass, explain why you think many communities no longer allow residents to burn fallen leaves each autumn.
7th Grade - Chapter 2 ONLINE REVIEW
Answer Section
MODIFIED TRUE/FALSE
1. ANS: F, chemical
PTS: 1 DIF: Webb's I OBJ: 1/1 STA: SC.A.1.3.5
2. ANS: T PTS: 1 DIF: Webb's I
OBJ: 1/1 STA: SC.A.1.3.5
3. ANS: T PTS: 1 DIF: Webb's I
OBJ: 1/1 STA: SC.A.1.3.5
4. ANS: T PTS: 1 DIF: Webb's I
OBJ: 1/1 STA: SC.A.1.3.5
5. ANS: F, chemical
PTS: 1 DIF: Webb's I OBJ: 4/2 STA: SC.A.1.3.5
6. ANS: F, Chemical
PTS: 1 DIF: Webb's I OBJ: 4/2 STA: SC.A.1.3.5
7. ANS: F, are
PTS: 1 DIF: Webb's I OBJ: 3/2 STA: SC.A.1.3.5
8. ANS: T PTS: 1 DIF: Webb's I
OBJ: 3/2 STA: SC.A.1.3.5
MULTIPLE CHOICE
9. ANS: A PTS: 1 DIF: Webb's I STA: SC.A.1.3.1
10. ANS: C PTS: 1 DIF: Webb's I STA: SC.A.1.3.1
11. ANS: A PTS: 1 DIF: Webb's I STA: SC.A.1.3.1
12. ANS: C PTS: 1 DIF: Webb's II STA: SC.A.1.3.1 SC.A.1.3.5
13. ANS: C PTS: 1 DIF: Webb's II STA: SC.A.1.3.1
14. ANS: A PTS: 1 DIF: Webb's I STA: SC.A.1.3.1 SC.A.1.3.5
15. ANS: D PTS: 1 DIF: Webb's II STA: SC.A.1.3.5
16. ANS: D PTS: 1 DIF: Webb's I STA: SC.A.1.3.5
17. ANS: A PTS: 1 DIF: Webb's I STA: SC.A.1.3.5
18. ANS: C PTS: 1 DIF: Webb's II STA: SC.A.1.3.5
19. ANS: C PTS: 1 DIF: Webb's I STA: SC.A.1.3.5
20. ANS: B PTS: 1 DIF: Webb's I STA: SC.A.1.3.5
21. ANS: D PTS: 1 DIF: Webb's II STA: SC.A.1.3.5 SC.G.2.3.4
22. ANS: B PTS: 1 DIF: Webb's I OBJ: 1/1
STA: SC.A.1.3.2 SC.A.1.3.5
23. ANS: B PTS: 1 DIF: Webb's I OBJ: 1/1
STA: SC.A.1.3.5
24. ANS: A PTS: 1 DIF: Webb's I OBJ: 1/1
STA: SC.A.1.3.5
25. ANS: A PTS: 1 DIF: Webb's II OBJ: 4/2
STA: SC.A.1.3.5
26. ANS: C PTS: 1 DIF: Webb's II OBJ: 4/2
STA: SC.A.1.3.5
27. ANS: D PTS: 1 DIF: Webb's I OBJ: 3/2
STA: SC.A.1.3.5
28. ANS: C PTS: 1 DIF: Webb's I OBJ: 3/2
STA: SC.A.1.3.5
29. ANS: B PTS: 1 DIF: Webb's II OBJ: 3/2
STA: SC.A.1.3.5
30. ANS: C PTS: 1
31. ANS: D PTS: 1
32. ANS: A PTS: 1
33. ANS: B PTS: 1
34. ANS: D PTS: 1
35. ANS: C PTS: 1
36. ANS: C PTS: 1
37. ANS: B PTS: 1
38. ANS: C PTS: 1
39. ANS: B PTS: 1
40. ANS: A PTS: 1
41. ANS: D PTS: 1
42. ANS: A PTS: 1
43. ANS: D PTS: 1
44. ANS: D PTS: 1
COMPLETION
45. ANS: chemical
PTS: 1 DIF: Webb's I OBJ: 3/2 STA: SC.A.1.3.5
46. ANS: physical
PTS: 1 DIF: Webb's I OBJ: 1/1 STA: SC.A.1.3.5
47. ANS: chemical
PTS: 1 DIF: Webb's I OBJ: 4/2 STA: SC.A.1.3.5
48. ANS: state
PTS: 1 DIF: Webb's I OBJ: 3/2 STA: SC.A.1.3.5
49. ANS: chemical property
PTS: 1
50. ANS: chemical change
PTS: 1
51. ANS: conservation of mass
PTS: 1
52. ANS: physical change
PTS: 1
53. ANS: density
PTS: 1
54. ANS: physical property
PTS: 1
55. ANS: boiling point
PTS: 1
56. ANS: behavior
PTS: 1
57. ANS: volume
PTS: 1
58. ANS: melting point
PTS: 1
59. ANS: state
PTS: 1
60. ANS: appearance
PTS: 1
61. ANS: physical properties
PTS: 1
62. ANS: chemical change
PTS: 1
63. ANS: chemical
PTS: 1
64. ANS: state
PTS: 1
65. ANS: liquid state
PTS: 1
66. ANS: amount
PTS: 1
67. ANS: Density
PTS: 1
68. ANS:
melting
boiling
PTS: 1
69. ANS: behavior
PTS: 1
70. ANS: chemical property
PTS: 1
71. ANS: Deposition
PTS: 1
72. ANS: Color
PTS: 1
73. ANS:
gained
released
PTS: 1
74. ANS:
gas
solid
PTS: 1
75. ANS: mass, law of conservation of mass
PTS: 1
76. ANS: physical
PTS: 1
77. ANS: physical
PTS: 1
78. ANS: chemical
PTS: 1
79. ANS: physical
PTS: 1
80. ANS: chemical
PTS: 1
81. ANS: physical
PTS: 1
82. ANS: chemical
PTS: 1
83. ANS: chemical
PTS: 1
MATCHING
84. ANS: A PTS: 1 DIF: Webb's II OBJ: 1/1
STA: SC.A.1.3.5
85. ANS: B PTS: 1 DIF: Webb's II OBJ: 1/1
STA: SC.A.1.3.5
86. ANS: B PTS: 1 DIF: Webb's II OBJ: 1/1
STA: SC.A.1.3.5
87. ANS: A PTS: 1 DIF: Webb's II OBJ: 1/1
STA: SC.A.1.3.5
88. ANS: C PTS: 1 DIF: Webb's II OBJ: 3/2
STA: SC.A.1.3.5
89. ANS: D PTS: 1 DIF: Webb's II OBJ: 3/2
STA: SC.A.1.3.5
90. ANS: A PTS: 1 DIF: Webb's II OBJ: 3/2
STA: SC.A.1.3.5
91. ANS: B PTS: 1 DIF: Webb's II OBJ: 3/2
STA: SC.A.1.3.5
92. ANS: J PTS: 1
93. ANS: B PTS: 1
94. ANS: E PTS: 1
95. ANS: H PTS: 1
96. ANS: K PTS: 1
97. ANS: F PTS: 1
98. ANS: G PTS: 1
99. ANS: D PTS: 1
100. ANS: A PTS: 1
101. ANS: I PTS: 1
102. ANS: L PTS: 1
103. ANS: C PTS: 1
SHORT ANSWER
104. ANS:
A chemical property is a characteristic that cannot be observed without altering the substance observed. A physical property is a characteristic that a person can observe without changing the composition of that substance.
PTS: 1 DIF: Webb's II STA: SC.A.1.3.1
105. ANS:
Changing state does not change the identity of the matter. Water is still water whether it is ice, liquid, or vapor. Chemical properties can't be observed without changing the substance.
PTS: 1 DIF: Webb's II OBJ: 1/1 STA: SC.A.1.3.5
106. ANS:
There could be a poisonous residue on the glassware, or a chemical change may have occurred, causing something to become poisonous.
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.1 SC.A.1.3.5
107. ANS:
The starting materials must differ because the materials produced during the explosions have different colors.
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.5
108. ANS:
Constant: color, taste, texture of skin; not constant: size, shape
PTS: 1 DIF: Webb's II OBJ: 1/1 STA: SC.A.1.3.5
109. ANS:
A gas can be the result of a change of state, which is a physical change. The boiling of water produces water vapor; opening a carbonated beverage releases dissolved carbon dioxide.
PTS: 1 DIF: Webb's II OBJ: 4/2 STA: SC.A.1.3.4
110. ANS:
The material is decomposing, which is a chemical change; heat is the evidence of change.
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.5
111. ANS:
Color is a physical property because it can be observed without changing the substance, but when new substances form during a chemical change, there may be a change in color because the new substances will have a different set of physical properties.
PTS: 1 DIF: Webb's II OBJ: 4/2 STA: SC.A.1.3.5
112. ANS:
The trimming and braiding are physical changes because they are changes in size and shape. The bleaching is a chemical change because it produces a change in color.
PTS: 1 DIF: Webb's II OBJ: 4/2 STA: SC.A.1.3.5
113. ANS:
A chemical change changes the substance. A physical change doesn't affect the basics of the substance.
PTS: 1 DIF: Webb's II OBJ: 2/1 STA: SC.A.1.3.5
114. ANS:
Raking the leaves into a pile and spreading the ashes are physical changes. Burning the leaves and the ashes being broken down by the lawn for fertilizer are chemical changes.
PTS: 1 DIF: Webb's II OBJ: 4/2 STA: SC.A.1.3.5
115. ANS:
The carbon dioxide gas produced indicates that a chemical change has occurred. The change in volume as the dough rises is an example of a physical change.
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.5
116. ANS:
shape; physical; The solid bracelet must be heated until it melts, then liquid gold must be poured into a ring-shaped mold and allowed to harden. The new ring will still have the same composition as the bracelet.
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.5
117. ANS:
Plastic doesn't rust when exposed to the oxygen in air and water. (Also, the plastic rebounds from gentle impacts, and a car with less density is more fuel efficient.)
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.5
118. ANS:
Possible choices: physically changing a banana by peeling and slicing; physically changing water by heating; physically changing oranges to make juice; chemically changing bread by toasting; chemically changing eggs or meat by cooking.
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.5
119. ANS:
chemical; the metal in the penny has combined with oxygen in the air
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.5
120. ANS:
The product of a chemical change can have very different physical and chemical properties from the original materials.
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.1 SC.A.1.3.5
121. ANS:
The rock salt dissolved in water from snow or rain. The water evaporated from the surface of the car leaving powdered salt, a physical change.
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.5
122. ANS:
Water can freeze and expand in the crevices of rocks, causing them to split into smaller pieces. Water can also dissolve materials from rocks.
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.1 SC.A.1.3.5
123. ANS:
size dependent: mass, weight, volume; size independent: density, melting/boiling point, solubility, ability to attract a magnet, state, color
PTS: 1 DIF: Webb's II OBJ: 1/1 STA: SC.A.1.3.1 SC.A.1.3.5
124. ANS:
The law of conservation of mass states that mass cannot be created or destroyed. This means that the mass of any substances present before a physical or chemical change is equal to the mass of the substances present after the change.
PTS: 1 DIF: Webb's II OBJ: 3/2 STA: SC.A.1.3.2 SC.A.1.3.5
125. ANS:
Answers may include mass, weight, volume.
PTS: 1
126. ANS:
Answers may include density, melting point, boiling point, solubility, ability to attract a magnet, state of matter, color.
PTS: 1
127. ANS:
Possible answers include: coloring the paper, crumpling the paper, tearing it, or dissolving it.
PTS: 1
128. ANS:
Burn it or dissolve it in acid.
PTS: 1
129. ANS:
Most people cause physical changes because they use notebook paper to take notes or write things on. Very few people burn notebook paper.
PTS: 1
130. ANS:
The tearing of paper is a physical change. The only changes in the paper caused by tearing are changes in size and shape. The burning of paper is a chemical change. During this change, paper is changed into ashes, smoke, and gases.
PTS: 1
131. ANS:
Both change the substance from what is first seen. Chemical changes are not easily reversed. Physical changes just change the observable parts of a substance, but the basic substance is unchanged.
PTS: 1
132. ANS:
The formation of the water drops indicates that water vapor in the air has condensed, or changed to a liquid, on the sides of the glass. Condensation is a physical change.
PTS: 1
133. ANS:
If the color change is caused by a reaction within the leaf, it is chemical. If it is caused by bird droppings or berry juice, it is physical.
PTS: 1
134. ANS:
Heating caused a chemical change to take place. The chemical properties of the new product have changed and a new substance has been formed.
PTS: 1
135. ANS:
Dissolving sugar in water is a physical change. Making cookies with sugar is a chemical change.
PTS: 1
136. ANS:
a. physical
b. physical
c. chemical
d. physical
e. chemical
PTS: 1
ESSAY
137. ANS:
Part A In the fall, the leaves of many trees begin to change color. This is a visible example of a chemical change that is occurring in the tree.
Part B In the fall, the chlorophyll in the tree’s leaves undergoes a chemical change into colorless chemicals. This allows different colors of pigment such as red and orange now to be seen.
PTS: 1 DIF: Webb's II STA: SC.A.1.3.5
138. ANS:
Mass, weight, and volume of an object are size dependent; they are greater or less, depending on the size of the object. Size-independent physical properties are the same, regardless of the paper’s size. Density, which is mass divided by volume, does not change with size.
PTS: 1
139. ANS:
Answers will vary. Look for answers that define chemical change and the law of conservation of mass and relate the mass of fallen leaves to an equal amount of particles that could pollute the air.
PTS: 1
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