Assume that the temperature and the amount of
gas are constant in the following problems.
1. The volume of a gas at 99.0 kPa is 300.0 mL. If
the pressure is increased to 188 kPa, what will
be the new volume?
158 mL
V2
V1P _1
P2
__(300.0 mL)(99.0 kPa)
188 kPa 158 mL
2. The pressure of a sample of helium in a
1.00-L container is 0.988 atm. What is the new
pressure if the sample is placed in a 2.00-L
container?
0.494 atm
P2 V1P _1
V2
__(1.00 L)(0.988 atm)
2.00 L 0.494 atm
3. Challenge Air trapped in a cylinder fitted
with a piston occupies 145.7 mL at 1.08 atm
pressure. What is the new volume when the
piston is depressed, increasing the pressure
by 25%?
117 mL
P2 1.08 atm (1.08 atm 0.25) 1.35 atm
V2
V1P _1
P2
__(145.7 mL)(1.08 atm)
1.35 atm 117 mL
Problem-Solving Lab
page 444
Lungs
Diaphragm
Ribs
1. Apply Boyle’s law to explain why air enters
your lungs when you inhale and leaves when
you exhale.
Boyle’s Law states that at constant temperature,
the volume of a gas varies inversely with
pressure. When you inhale, lung volume
increases. Pressure decreases and air moves
in. When you exhale, lung volume decreases.
Pressure increases and air moves out.
2. Explain what happens inside the lungs when
a blow to the abdomen knocks the wind out of
a person. Use Boyle’s law to determine your
answer.
When someone is hit in the abdomen, the
diaphragm is temporarily paralyzed. When the
diaphragm does not move up and down, lung
volume does not change. If the volume does not
change, pressure inside the lungs does not change,
and air is not drawn in and out of the lungs.
3. Infer Parts of the lungs lose elasticity and
become enlarged when a person has emphysema.
From what you know about Boyle’s law, why
does this condition affect breathing?
If parts of the lungs lose elasticity, it is more
difficult to change lung volume. With less change
in volume, there is less difference in pressure.
With less difference in pressure, it is more difficult
for air to enter or exit the lungs.
13
Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
254 Chemistry: Matter and Change • Chapter 13 Solutions Manual
CHAPTER 13 SOLUTIONS MANUAL
4. Explain why beginning scuba divers are taught
never to hold their breath while ascending from
deep water.
As a scuba diver ascends, pressure decreases.
A decrease in pressure results in an increase
in volume. If a diver holds his or her breath
while ascending, air volume in the lungs would
increase.
Practice Problems
pages 446–450
4. What volume will the gas in the balloon below
occupy at 250 K?
4.3 L
350 K
3.1 L
V2
V1T _2
T1
__(4.3 L)(250 K)
350 K 3.1 L
5. A gas at 89ºC occupies a volume of 0.67 L.
At what Celsius temperature will the volume
increase to 1.12 L?
330°C
T1 89°C 273 362 K
T2
T_1V2
V1
__(362 K)(1.12 L)
0.67 L 605 K
605 273 332°C 330°C
6. The Celsius temperature of a 3.00-L sample of
gas is lowered from 80.0ºC to 30.0ºC. What
will be the resulting volume of this gas?
2.58 L
T1 80.0°C 273 353 K
T2 30.0°C 273 303 K
V2
V1T _2
T1
__(3.00 L)(303 K)
353 K 2.58 L
7. Challenge A gas occupies 0.67 L at 350 K.
What temperature is required to reduce the
volume by 45%?
190 K
V2 0.67 L (0.67 L 0.45) 0.37 L
T2
T_1V2
V1
(350 K)(0.37 L )
__
0.67 L 190 K
Assume that the volume and the amount of gas
are constant in the following problems.
8. The pressure in an automobile tire is 1.88 atm
at 25.0°C. What will be the pressure if the
temperature increases to 37.0°C?
1.96 atm
T1 25.0°C 273 298 K
T2 37.0°C 273 310 K
P2
P1T _2
T1
__(1.88 atm)(310 K)
298 K 1.96 atm
9. Helium gas in a 2.00-L cylinder is under
1.12 atm pressure. At 36.5ºC, that same gas
sample has a pressure of 2.56 atm. What
was the initial temperature of the gas in the
cylinder?
138°C
T2 36.5°C 273 309.5 K
T1
T2P _1
P2
__(309.5 K)(1.12 atm)
2.56 atm 135 K
135 K 273 138°C
10. Challenge If a gas sample has a pressure
of 30.7 kPa at 0.00ºC, by how many degrees
Celsius does the temperature have to increase to
cause the pressure to double?
273°C
T1 0.00°C 273 273 K
P2 (30.7 kPa)(2) 61.4 kPa
T2
T1P _2
P1
__(273 K)(61.4 kPa)
30.7 kPa 546 K
546 K 273 273°C
The temperature must increase by 273°C.
