Chapter 10 Gases Homework Problems
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#2. Assume that you have a sample of gas in a container with a movable piston. (a)
Redraw the container to show what it might look like if the temperature of the gas is
increased from 300 K to 500 K while the pressure is kept constant. (b) Redraw the
container to show what it might look like if the pressure on the piston is increased from
1.0 atm to 2.0 atm while the temperature is kept constant.
#8. Consider the following drawing. (a) If the curves A and B are
two different gases, He and O2 at the same temperature, which
is which? Explain. (b) If A and B refer to the same gas at two
different temperatures, which represents the higher
temperature?
#11. How does a gas differ from a liquid with respect to the following properties? (a) density (b)
compressibility (c) ability to mix with other substances of the same phase to form a homogeneous mixture
#19. The typical atmospheric pressure on the top of Mt. Everest (29,028 ft) is about 265 torr. Convert the
pressure to (a) atm (b) mm Hg (c) pascals (d) bars
#23. If the atmospheric pressure is 0.985 atm, what
is the pressure of the enclosed gas in each of the
three drawings? (h1 = 52 cm, h2 = 67 mm, h3=10.3
cm)
#28. Nitrogen and hydrogen gases react to form ammonia gas as follows:
N2 + 3 H2  2 NH3
At a certain temperature and pressure, 1.2 L of N2 reacts with 3.6 L of H2. If all of the N2 and H2 are
consumed, what volume of NH3, at the same temperature and pressure, will be produced?
#33. Complete the following table for an ideal gas:
P
2.00 atm
0.300 atm
650 torr
? atm
V
1.00 L
0.250 L
?L
585 mL
n
0.500 mol
? mol
0.333 mol
0.250 mol
T
?K
27 0C
350 K
295 K
#37. Calculate the number of molecules in a deep breath of air whose volume is 2.25 L at a body
temperature of 37 0C and a pressure of 735 torr.
#43. In an experiment reported in the scientific literature, male cockroaches were made to run at different
speeds on a mini-treadmill while the oxygen consumption was measured. In one hour the average cockroach
running at 0.08 km/hr consumed 0.8 mL of O2 at 1 atm pressure and 24 0C per gram of insect weight. (a)
How many moles of O2 would be consumed in 1-hr by a 5.2 gram cockroach moving at this speed. (b) The
same cockroach is caught by a child and placed in a 1-qt fruit jar with a tight lid. Assuming the same level of
continuous activity, will the cockroach consume more than 20% of the available O2 in an 18-hr period?
(Assume 21% O2)
#45. Which gas is most dense at 1.00 atm and 298 K? CO2, N2O, or Cl2 Explain.
#49. (a) Calculate the density of NO2 gas at 0.970 atm and 35 0C. (b) Calculate the molar mass of a gas if 2.50
grams occupies 0.875 L at 685 torr and 35 0C.
#53. Magnesium can be used as a “getter” in evacuated enclosures, to react with the last traces of oxygen. If
an enclosure of 0.382 L has a partial pressure of O2 of 3.5 x 10-6 torr at 27 0C, what mass of magnesium will
react?
#55. Calculate the volume of CO2 produced at body temperature (37 0C) and 0.970 atm when 24.5 grams of
glucose C6H12O6 is consumed in the reaction of the metabolism of glucose.
#59. A 2.0-L container contains nitrogen gas at a pressure of 1.0 atm, which is connected to a 3.0-L
container that contains oxygen gas at 2.0 atm. If the stopcock is opened between them, allowing them to
mix, what is the new pressure of the system?
#65. A mixture of gases contains 0.75 mol N2, 0.30 mol O2, and 0.15 mol CO2. If the total pressure of the
mixture is 1.56 atm, what is the partial pressure of each component?
#73. What property or properties of gases can you point to that support the assumption that most of the
volume in a gas is empty space?
#77. (a) Place the following gases in order of increasing average molecular speed at 25 0C: Ne, HBr, SO2, NF3,
CO. (b) Calculate the rms speed of NF3 molecules at 25 0C.
#83. (a) List two experimental conditions under which gases deviate from ideal behavior. (b) List two
reasons why the gases deviate from ideal behavior. (c) Explain how the function PV/RT can be used to show
how gases behave nonideally.
#87. Calculate the pressure exerted by 1.00 mol Cl2 confined to 5.00 L at 25 0C. (a) First use the ideal gas
equation and (b) then use the Van der Waals equation for your calculation. (The Van der Waals constant for
Cl2 is a = 6.49 L2atm/mol2 b = 0.0562 L/mol) (c) Why is the difference between the results for an ideal gas
and a real gas greater when the gas is confined to 5.00 L compared to 22.4 L?