Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question. You may use a
calculator to complete these problems.

 1.  At
constant temperature, 14.0 L of O_{2} at 0.882 atm is compressed to 1.75 L. What is the final
pressure of O_{2}? a.  0.111 atm  b.  0.142
atm  c.  7.06
atm  d.  21.6
atm  e.  27.8
atm   

 2.  If
the volume of a confined gas is quadrupled while its temperature remains constant, what change will
be observed? a.  The pressure of
the gas will decrease to 1/4 its original value.  b.  The pressure of
the gas will quadruple.  c.  The density of the gas will decrease to 1/2 its original
value.  d.  The average velocity of the molecules will
quadruple.  e.  The average velocity of the molecules will
double.   

 3.  A
balloon is filled with He gas to a volume of 3.22 L at 32 °C. The balloon is placed in liquid nitrogen until its
temperature reaches 132 °C. Assuming the pressure remains constant, what is the volume of the
cooled balloon? a.  0.628
L  b.  0.781
L  c.  1.24
L  d.  1.49
L  e.  6.96
L   

 4.  Avogadro's hypothesis states that equal volumes of gases under the same conditions of
temperature and pressure have equal ____. a.  densities  b.  particle
velocities  c.  molar masses  d.  numbers of
particles  e.  masses   

 5.  Which
of the following relationships are true for gases?
1.  The number of moles of a gas is directly proportional to its
volume (at constant pressure).  2.  The pressure of a gas is inversely proportional to its
temperature in Kelvins (at constant volume).  3.  The volume of a gas is directly proportional to its pressure
(at constant temperature).   
a.  1
only  b.  2
only  c.  3
only  d.  1 and
2  e.  2 and
3   

 6.  If
3.67 g CO_{2} gas is introduced into an evacuated 2.50 L flask at 65 °C, what is the
pressure inside the flask? (R = 0.08206 L·atm/mol·K) a.  0.178
atm  b.  0.445
atm  c.  0.925
atm  d.  40.7
atm  e.  496
atm   

 7.  A
mass of 1.663 g of an unknown gas is introduced into an evacuated 2.00 L flask. If the pressure in
the flask is 0.544 atm at 78 °C, which of the following gases might be in the flask? (R =
0.08206 L·atm/mol·K) a.  N_{2}  b.  C_{2}H_{2}  c.  NH_{3}  d.  HCl  e.  N_{2}O   

 8.  What
volume of O_{2}, measured at 91.2 °C and 743 mm Hg, will be produced by the decomposition of 4.88 g
KClO_{3}? (R = 0.08206 L·atm/mol·K)
2 KClO_{3}(s) ® 2 KCl(s) + 3 O_{2}(g)
a.  0.305
L  b.  1.22
L  c.  1.83
L  d.  24.0
L  e.  37.4
L   

 9.  Ammonia gas is synthesized according to the balanced equation
below.
N_{2}(g) + 3 H_{2}(g) ® 2
NH_{3}(g)
If 2.75 L N_{2} react with 7.75 L
H_{2}, what is the theoretical yield (in liters) of NH_{3}? Assume that the volumes
of reactants and products are measured at the same temperature and pressure. a.  2.75
L  b.  5.17
L  c.  5.50
L  d.  10.5
L  e.  15.5
L   

 10.  The
empirical formula of a certain hydrocarbon is CH_{2}. When 0.120 mole of the hydrocarbon is
completely combusted with excess oxygen, 17.7 L CO_{2} gas is produced at 27 °C and 1.00 atm.
What is the molecular formula of the hydrocarbon? (R = 0.08206
L·atm/mol·K) a.  C_{2}H_{2}  b.  C_{2}H_{4}  c.  C_{3}H_{6}  d.  C_{5}H_{10}  e.  C_{6}H_{12}   

 11.  An
unknown gaseous hydrocarbon contains 85.63 % C. Its density is 0.426 g/L at 0.465 atm and 373 K. What
is the molecular formula of the gas? (R = 0.08206 L·atm/mol·K) a.  C_{2}H_{4}  b.  C_{3}H_{6}  c.  C_{4}H_{8}  d.  C_{5}H_{10}  e.  C_{6}H_{12}   

 12.  Carbon monoxide reacts with oxygen to form carbon dioxide.
2 CO(g) + O_{2}(g) ® 2 CO_{2}(g)
In a 1.00 L flask, 2.40 atm of CO reacts with 4.50 atm of
O_{2}. Assuming that the temperature remains constant, what is the final pressure in the
flask? a.  1.20
atm  b.  2.40
atm  c.  3.30
atm  d.  3.60
atm  e.  5.70
atm   

 13.  A
mixture of He and O_{2} is placed in a 4.00 L flask at 32 °C. The partial
pressure of the He is 2.7 atm and the partial pressure of the O_{2} is 1.4 atm. What is the
mole fraction of O_{2}? a.  0.224  b.  0.341  c.  0.481  d.  0.518  e.  0.659   

 14.  Which
of the following are postulates of kineticmolecular theory of gases?
1.  The distance between gas molecules is large in comparison to
their size.  2.  Gas molecules are in constant, random
motion.  3.  The kinetic
energy of gas particles is proportional to the Kelvin temperature.   
a.  1 only  b.  2
only  c.  3
only  d.  1 and
2  e.  1, 2, and
3   

 15.  What
is the rootmeansquare velocity of ethane molecules (C_{2}H_{6}) at 273
K? a.  15.0
m/s  b.  47.2
m/s  c.  275
m/s  d.  476
m/s  e.  652
m/s   

 16.  Place
the following gases in order of increasing average velocity at 325 K: Ar, Ne, N_{2}, and
SO_{2}. a.  Ar < Ne <
N_{2} < SO_{2}  b.  Ne < Ar < N_{2} <
SO_{2}  c.  N_{2} < SO_{2} < Ne <
Ar  d.  SO_{2}
< Ar < N_{2} < Ne  e.  Ar = Ne = N_{2} =
SO_{2}   

 17.  The
average velocity of a gas molecule is a.  inversely proportional to its kinetic
energy.  b.  directly proportional to the gas constant,
R.  c.  directly proportional to the square root of its temperature in
K.  d.  inversely
proportional to the square of its mass.  e.  directly proportional to the square root of its
mass.   

 18.  Carbon monoxide gas diffuses through a barrier at a rate of 0.480 mL/minute. If an
unknown gas diffuses through the same barrier at a rate of 0.277 mL/minute, what is the molar mass of
the gas? a.  9.33
g/mol  b.  21.3 g/mol  c.  36.9
g/mol  d.  44.01 g/mol  e.  84.1
g/mol   

 19.  Nonideal behavior for a gas is most likely to be observed under conditions
of a.  high temperature
and low pressure.  b.  high temperature and high pressure.  c.  low temperature
and low pressure.  d.  standard temperature and pressure.  e.  low temperature
and high pressure.   

 20.  One
way in which real gases differ from ideal gases is that the molecules of a real gas a.  are attracted to
each other.  b.  are liquids or solids above 273.15 K.  c.  are always
polar.  d.  move in circles rather than straight
paths.  e.  have no kinetic energy.   

 21.  If
4.00 g S_{8} react with 4.25 L O_{2} at 39 °C and 1.00 atm, what is the maximum mass of SO_{3}
produced? (R = 0.08206 L·atm/mol·K)
S_{8}(s) + 12 O_{2}(g) ® 8
SO_{3}(g)
a.  2.83 g  b.  8.86
g  c.  9.99
g  d.  13.3
g  e.  19.9
g   

 22.  If a
gas effuses 1.618 times faster than Kr, what is its molar mass? a.  18.02
g/mol  b.  28.01 g/mol  c.  32.01
g/mol  d.  51.79 g/mol  e.  65.88
g/mol   
