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Supp. Ex. - 06 Matter as particles
Great ideas in science (The University of Hong Kong)
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Living Science (Second Edition) Supplementary Exercise
Unit 6
Unit 6 Matter as particles
A Multiple-choice questions
1
Which of the following is solid at room temperature?
A
Carbon dioxide
B
Mercury
C
Water
D
Charcoal
D
The following graph shows the temperature change of ice. Which part of the
graph contains solid only?
Temperature (oC)
*2
100
D
B
C
A
0
time
A
3
A cube of butter melts at 45 oC, it starts to solidify at
A
45 oC
B
55 oC
C
65 oC
D
75 oC
A
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Living Science (Second Edition) Supplementary Exercise
4
Unit 6
In a solid, the particles
A
cannot vibrate.
B
cannot move around.
C
do not have space between them.
D
do not have a regular pattern of arrangement.
B
5
Which of the following can be explained with the particle theory?
(1) Brownian motion
(2) Thermal expansion and contraction
(3) Air pressure
A
(1) and (2) only
B
(1) and (3) only
C
(2) and (3) only
D
(1), (2) and (3)
D
6
When adding a drop of ink into a beaker of water, the ink spreads out. Which of
the following explanations is correct?
A
B
C
D
Only the ink particles move and go between water particles.
Only water particles move and go between ink particles.
Both ink and water particles move and they mix together.
Ink particles move faster than water particles.
C
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Living Science (Second Edition) Supplementary Exercise
7
Unit 6
Which of the following statements about the air pressure at the peak of a
mountain and at the sea level is correct?
A
The air pressure is greater at the peak of a mountain than at the sea level.
B
The air pressure is smaller at the peak of a mountain than at the sea level.
C
The air pressure is the same at the peak of a mountain and at the sea level.
D
The air pressure at the peak of a mountain cannot be measured.
B
*8
Which of the following diagrams about a submarine is not correct?
key : air tank of the submarine filled with seawater
A Sink
B Sink
C Float
D Sink to certain depth
B
9
What is the reason that alcohol is used inside a thermometer?
A
It is easily seen.
B
It is non-toxic.
C
It expands and contracts easily.
D
It can be refilled easily.
C
10
The following shows the densities of different materials. If they are put together
in a container, what is the order of their position from the top to the bottom?
Material
3
Density (g/cm )
A
B
C
D
Polystyrene
Mercury
Water
Oil
0.03
13.5
1
0.9
Polystyrene, mercury, water, oil
Polystyrene, oil, water, mercury
Oil, water, mercury, polystyrene
Water, polystyrene, oil, mercury
B
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Living Science (Second Edition) Supplementary Exercise
B True or false questions
1
T
When an ice melts, the temperature remains unchanged.
2
The freezing point of a substance is equal to the melting point of that
substance.
T
3
If a substance does not have a fixed shape and takes up the shapes of
the containers, it is a gas.
F
4
The rate of dissolving increases at high temperature because the
solvent particles and the solute particles move faster and they mix
together faster.
T
5
T
The density of the air decreases with increase in altitude.
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Unit 6
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Living Science (Second Edition) Supplementary Exercise
Unit 6
C Fill-in-the-blanks
1
Solid, liquid and gas are the three
states
of matter.
2
When the temperature drops to the
will turn into solid.
freezing
point, a liquid
3
If a substance has one kind of atoms only, it is called an
element
4
We can float on the water because the
than water.
density
.
of our body is less
5
When heating a bimetallic strip, the strip bends towards the iron side. It is
because the brass
more than the iron.
expands
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Living Science (Second Edition) Supplementary Exercise
Unit 6
D Short questions
*
E1 In winter, the air pressure is usually high. Give an explanation with the particle
theory.
Answer:
In winter, the air temperature is lower. Therefore, the air becomes denser. There are
more collisions of air particles on the ground, producing higher air pressure.
2
The following table shows the melting points and boiling points of different
substances. State which is solid, liquid and gas at room temperature (25 oC).
Substance
Carbon
Melting point ( C)
Argon
190
Boling point (oC)
186
o
Nickel
3500
Mercury
39
4827
357
2732
1453
Answer:
Gas: argon
Liquid: mercury
Solid: carbon, nickel
*3
Explain why you cannot prepare 100 cm3 of dilute alcohol from mixing 50 cm3
of water and 50 cm3 of alcohol together.
Answer:
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Living Science (Second Edition) Supplementary Exercise
Unit 6
There are spaces between the water particles and alcohol particles. Water particles and
alcohol particles can go into these spaces. Therefore the volume of mixing 50 cm3 of
water and 50 cm3 of alcohol is less than 100 cm3.
*4 Swim bladder is a sac containing gas in the body of some fish. Fish can release
gas into the swim bladder or withdraw the gas out of the swim bladder so that it
can float or sink. If the fish wants to float on the water surface, should the swim
bladder be filled with more gas or less gas? Explain you answer.
swim bladder
Answer:
The swim bladder should be filled with more gas. When it is filled with more gas, the
density of the fish is lower. Therefore, it can float on the water surface.
5
it.
Explain why an empty drink box expands when air is blown into
blow air
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Living Science (Second Edition) Supplementary Exercise
Answer:
The box expands because there are more air particles inside the box, producing
greater air pressure than the outside.
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Unit 6
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Living Science (Second Edition) Supplementary Exercise
E
Long questions
The following graph shows the cooling of a gas.
Temperature (oC)
*1
Unit 6
80 A
60 B
40 C
a
20 At which temperature does the gas start to become liquid?
b
0
time
At which temperature does the gas completely
become liquid?
c
In which phase (A, B or C) do the particles have the slightest movement?
d
Draw diagrams to show the relative density of the particles at phase A and
C.
Answer:
a
40 oC
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Living Science (Second Edition) Supplementary Exercise
b
c
d
40 oC
C
particles at phase A
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particles at phase C
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Unit 6
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Living Science (Second Edition) Supplementary Exercise
2
Unit 6
A strip of metal is originally 10 cm long. After it is intensely heated, it becomes
lengthened for 2 mm.
10 cm
a
Calculate the percentage of expansion of the metal strip.
b
Explain why the metal strip expands when it is being heated.
a diagram to show the particles of the metal
before being heated
A
B
C
D
c
Which of the above diagrams (A to D) correctly shows the particles of the
metal after it is heated?
d
Which of the above diagrams (A to D) shows the particles of the metal
after it is melted?
Answer:
a
percentage of expansion of the metal strip = 2 mm / 100 mm  100 = 2
b
When the metal strip is being heated, the particles of the metal get more energy
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Living Science (Second Edition) Supplementary Exercise
Unit 6
and they can vibrate more vigorously. The spaces between them become larger,
so the metal strip expands.
c
C
d
B
**3 The following diagram shows a hot air balloon. Flame is given out at the nozzle.
The fuel tanks provide fuels for it to burn. The flame heats up the air in the
balloon, then the balloon rises.
flame
nozzle
fuel tanks
a
Why do the balloon rise in the air?
b
What is the change in the atmospheric pressure when the balloon gets
higher and higher?
c
Explain why the balloon can only rise to a certain level and cannot go
higher.
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Living Science (Second Edition) Supplementary Exercise
Unit 6
Answer:
a
The air inside the balloon is hot, so its density is lower than the surrounding air.
As a result, the balloon floats in the air.
b
The atmospheric pressure is decreasing when the balloon gets higher and higher.
c
The density of the air is decreasing with increasing altitude. At a certain level,
the density of the air becomes lower than the density of the balloon, so the
balloonstops rising at this level.
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