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Chemistry: The Central Science, 13e (Brown et al.)
Chapter 10 Gases
10.1 Multiple Choice Questions
1) Which of the following statements about gases is false?
A) Gases are highly compressible.
B) Distances between molecules of gas are very large compared to bond distances within molecules.
C) Non-reacting gas mixtures are homogeneous.
D) Gases expand spontaneously to fill the container they are placed in.
E) All gases are colorless and odorless at room temperature.
2) Of the following, ________ has a slight odor of bitter almonds and is toxic.
A) NH3
B) N2O
C) CO
D) CH4
E) HCN
3) Of the following, ________ has the odor of rotten eggs.
A) NH3
B) H2S
C) CO
D) NO2
E) HCN
4) One significant difference between gases and liquids is that ________.
A) a gas is made up of molecules
B) a gas expands to fill its container
C) a gas may consist of both elements and compounds
D) gases are always mixtures
E) All of the above answers are correct.
5) Gaseous mixtures ________.
A) can only contain molecules
B) are all heterogeneous
C) can only contain isolated atoms
D) are all homogeneous
E) must contain both isolated atoms and molecules
6) Which of the following equations shows an incorrect relationship between pressures given in terms of
different units?
A) 1.20 atm = 122 kPa
B) 152 mm Hg = 2.03 × 104 Pa
C) 0.760 atm = 578 mm Hg
D) 1.0 torr = 2.00 mm Hg
E) 1.00 atm = 760 torr
7) The pressure exerted by a column of liquid is equal to the product of the height of the column times the
gravitational constant times the density of the liquid, P = ghd. How high a column of water (d = 1.0 g/mL)
would be supported by a pressure that supports a 713 mm column of mercury (d = 13.6 g/mL)?
A) 14 mm
B) 52 mm
C) 713 mm
D) 1.2 × 104 mm
E) 9.7 × 103 mm
8) The pressure exerted by a column of liquid is equal to the product of the height of the column times the
gravitational constant times the density of the liquid, P = ghd. How high a column of methanol
(d = 0.79 g/mL) would be supported by a pressure that supports a 713 mm column of mercury
(d = 13.6 g/mL)?
A) 713 mm
B) 41 mm
C) 1.2 × 104 mm
D) 9.7 × 103 mm
E) 17 mm
9) Which statement about atmospheric pressure is false?
A) As air becomes thinner, its density decreases.
B) Air actually has weight.
C) With an increase in altitude, atmospheric pressure increases as well.
D) The warmer the air, the lower the atmospheric pressure.
E) Atmospheric pressure prevents water in lakes, rivers, and oceans from boiling away.
10) In ideal gas equation calculations, expressing pressure in Pascals (Pa), necessitates the use of the gas
constant, R, equal to ________.
A) 0.08206 atm L mol-1K-1
B) 8.314 -Pa/mol-K
C) 62.36 L torr mol-1K-1
D) 1.987 cal mol-1K-1
E) none of the above
11) The first person to investigate the relationship between the pressure of a gas and its volume was
________.
A) Amadeo Avogadro
B) Lord Kelvin
C) Jacques Charles
D) Robert Boyle
E) Joseph Louis Gay-Lussac
12) Of the following, ________ is a correct statement of Boyle's law.
A) PV = constant
B) = constant
C) = constant
D) = constant
E) = constant
13) "Isothermal" means ________.
A) at constant pressure
B) at constant temperature
C) at variable temperature and pressure conditions
D) at ideal temperature and pressure conditions
E) that ΔHrxn = 0
14) Of the following, ________ is a valid statement of Charles' law.
A) = constant
B) = constant
C) PV = constant
D) V = constant × n
E) V = constant × P
15) Which one of the following is a valid statement of Avogadro's law?
A) = constant
B) = constant
C) PV = constant
D) V = constant × n
E) V = constant × P
16) The volume of an ideal gas is zero at ________.
A) 0 °C
B) -45 °F
C) -273 K
D) -363 K
E) -273 °C
17) Of the following, only ________ is impossible for an ideal gas.
A) =
B) =
C) =
D) =
E) = = 0
18) The molar volume of a gas at STP is ________ L.
A) 0.08206
B) 62.36
C) 1.00
D) 22.4
E) 14.7
19) Standard temperature and pressure (STP), in the context of gases, refers to ________.
A) 298.15 K and 1 atm
B) 273.15 K and 1 atm
C) 298.15 K and 1 torr
D) 273.15 K and 1 pascal
E) 273.15 K and 1 torr
20) Sodium bicarbonate is reacted with concentrated hydrochloric acid at 37.0 °C and 1.00 atm. The
reaction of 6.00 kg of bicarbonate with excess hydrochloric acid under these conditions will produce
________ L of CO2.
A) 1.09 × 102
B) 2.85 × 104
C) 1.82 × 104
D) 8.70 × 102
E) 1.82 × 103
21) Sodium bicarbonate is reacted with concentrated hydrochloric acid at 25.0 °C and 1.50 atm. The
reaction of 7.75 kg of bicarbonate with excess hydrochloric acid under these conditions will produce
________ L of CO2.
A) 1.82 × 103
B) 2.85 × 104
C) 1.82 × 104
D) 1.50 × 103
E) 8.70 × 102
22) The volume of a sample of gas (2.49 g) was 752 mL at 1.98 atm and 62 °C. The gas is ________.
A) SO2
B) SO3
C) NH3
D) NO2
E) Ne
23) The density of NO2 in a 4.50 L tank at 760.0 torr and 25.0 °C is ________ g/L.
A) 1.64
B) 9.30
C) 1.68
D) 1.88
E) 3.27
24) A 255 mL round-bottom flask is weighed and found to have a mass of 114.85 g. A few milliliters of an
easily vaporized liquid are added to the flask and the flask is immersed in a boiling water bath. All of the
liquid vaporizes at the boiling temperature of water, filling the flask with vapor. When all of the liquid
has vaporized, the flask is removed from the bath, cooled, dried, and reweighed. The new mass of the
flask and the condensed vapor is 115.23 g. Which of the following compounds could the liquid be?
(Assume the ambient pressure is 1 atm.)
A) C4H10
B) C3H7OH
C) C2H6
D) C2H5OH
E) C4H9OH
25) A sample of an unknown volatile liquid was injected into a Dumas flask mflask = 27.0928 g,
vflask = 0.1040 L) and heated until no visible traces of the liquid could be found. The flask and its
contents were then rapidly cooled and reweighed (mflask + vapor = 27.4593 g). The atmospheric pressure
and temperature during the experiment were 0.976 atm and 18.0 °C, respectively. The unknown volatile
liquid was ________.
A) C6H12
B) C6H14
C) C7H14
D) C7H16
E) C6H6
26) The density of air at STP is 1.285 g/L. Which of the following cannot be used to fill a balloon that will
float in air at STP?
A) CH4
B) NO
C) Ne
D) NH3
E) HF
27) The average kinetic energy of the particles of a gas is directly proportional to ________.
A) the rms speed
B) the square of the rms speed
C) the square root of the rms speed
D) the square of the particle mass
E) the particle mass
28) The kinetic-molecular theory predicts that pressure rises as the temperature of a gas increases because
________.
A) the average kinetic energy of the gas molecules decreases
B) the gas molecules collide more frequently with the wall
C) the gas molecules collide less frequently with the wall
D) the gas molecules collide more energetically with the wall
E) both the gas molecules collide more frequently with the wall and the gas molecules collide more
energetically with the wall
29) According to kinetic-molecular theory, in which of the following gases will the root-mean-square
speed of the molecules be the highest at 200 °C?
A) HCl
B) Cl2
C) H2O
D) SF6
E) None. The molecules of all gases have the same root-mean-square speed at any given temperature.
30) According to kinetic-molecular theory, if the temperature of a gas is raised from 100 °C to 200 °C, the
average kinetic energy of the gas will ________.
A) double
B) increase by a factor of 1.27
C) increase by a factor of 100
D) decrease by half
E) decrease by a factor of 100
31) Which of the following is not part of the kinetic-molecular theory?
A) Atoms are neither created nor destroyed by ordinary chemical reactions.
B) Attractive and repulsive forces between gas molecules are negligible.
C) Gases consist of molecules in continuous, random motion.
D) Collisions between gas molecules do not result in the loss of energy.
E) The volume occupied by all of the gas molecules in a container is negligible compared to the volume of
the container.
32) Of the following gases, ________ will have the greatest rate of effusion at a given temperature.
A) NH3
B) CH4
C) Ar
D) HBr
E) HCl
33) A tank containing both HF and HBr gases developed a leak. The ratio of the rate of effusion of HF to
the rate of effusion of HBr is ________.
A) 4.04
B) 0.247
C) 2.01
D) 0.497
E) 16.3
34) At 333 K, which of the pairs of gases below would have the most nearly identical rates of effusion?
A) N2O and NO2
B) CO and N2
C) N2 and O2
D) CO and CO2
E) NO2 and N2O4
35) At STP, the ratio of the root-mean-square speed of CO2 to that of SO2 is ________.
A) 2.001
B) 2.119
C) 1.000
D) 1.207
E) 1.456
36) Arrange the following gases in order of increasing average molecular speed at 25 °C.
He, O2, CO2, N2
A) He < N2 < O2 < CO2
B) He < O2 < N2 < CO2
C) CO2 < O2 < N2 < He
D) CO2 < N2 < O2 < He
E) CO2 < He < N2 < O2
37) Arrange the following gases in order of increasing average molecular speed at 25 °C.
Cl2, O2, F2, N2
A) Cl2 < F2 < O2 < N2
B) Cl2 < O2 < F2 < N2
C) N2 < F2 < Cl2 < O2
D) Cl2 < F2 < N2 < O2
E) F2 < O2 < N2 < Cl2
38) Which one of the following gases would have the highest average molecular speed at 25 °C?
A) O2
B) N2
C) CO2
D) CH4
E) SF6
39) A sample of oxygen gas (O2) was found to effuse at a rate equal to three times that of an unknown
gas. The molecular weight of the unknown gas is ________ g/mol.
A) 288
B) 96
C) 55
D) 4
E) 10.7
40) A sample of oxygen gas was found to effuse at a rate equal to two times that of an unknown gas. The
molecular weight of the unknown gas is ________ g/mol.
A) 64
B) 128
C) 8
D) 16
E) 8.0
41) A mixture of two gases was allowed to effuse from a container. One of the gases escaped from the
container 1.43 times as fast as the other one. The two gases could have been ________.
A) CO and SF6
B) O2 and Cl2
C) CO and CO2
D) Cl2 and SF6
E) O2 and SF6
42) A mixture of carbon dioxide and an unknown gas was allowed to effuse from a container. The carbon
dioxide took 1.25 times as long to escape as the unknown gas. Which one could be the unknown gas?
A) Cl2
B) CO
C) HCl
D) H2
E) SO2
43) How much faster does 235UF6 effuse than 238UF6?
A) 1.013 times as fast
B) 1.009 times as fast
C) 1.004 times as fast
D) 1.006 times as fast
E) 1.018 times as fast
44) An ideal gas differs from a real gas in that the molecules of an ideal gas ________.
A) have no attraction for one another
B) have appreciable molecular volumes
C) have a molecular weight of zero
D) have no kinetic energy
E) have an average molecular mass
45) A real gas will behave most like an ideal gas under conditions of ________.
A) high temperature and high pressure
B) high temperature and low pressure
C) low temperature and high pressure
D) low temperature and low pressure
E) STP
46) Which one of the following gases would deviate the least from ideal gas behavior?
A) Ne
B) CH3Cl
C) Kr
D) CO2
E) F2
14
47) Which noble gas is expected to show the largest deviations from the ideal gas behavior?
A) helium
B) neon
C) argon
D) krypton
E) xenon
48) The van der Waals equation for real gases recognizes that ________.
A) gas particles have non-zero volumes and interact with each other
B) molar volumes of gases of different types are different
C) the non-zero volumes of gas particles effectively decrease the amount of "empty space" between them
D) the molecular attractions between particles of gas decreases the pressure exerted by the gas
E) all of the above statements are true
49) When gases are treated as real, via use of the van der Waals equation, the actual volume occupied by
gas molecules ________ the pressure exerted and the attractive forces between gas molecules ________ the
pressure exerted, as compared to an ideal gas.
A) decreases, increases
B) increases, increases
C) increases, decreases
D) does not affect, decreases
E) does not affect, increases
10.2 Bimodal Questions
1) A gas at a pressure of 10.0 Pa exerts a force of ________ N on an area of 5.5 m2.
A) 55
B) 0.55
C) 5.5
D) 1.8
E) 18
2) A gas at a pressure of 325 torr exerts a force of ________ N on an area of 5.5 m2.
A) 1.8 × 103
B) 59
C) 2.4 × 105
D) 0.018
E) 2.4
3) A gas vessel is attached to an open-end manometer containing a nonvolatile liquid of density 0.791
g/mL as shown below.
The difference in heights of the liquid in the two sides of the manometer is 43.4 cm when the atmospheric
pressure is 755 mm Hg. Given that the density of mercury is 13.6 g/mL, the pressure of the enclosed gas is
________ atm.
A) 1.03
B) 0.967
C) 0.993
D) 0.990
E) 0.987
4) A gas vessel is attached to an open-end manometer filled with a nonvolatile liquid of density 0.993
g/mL as shown below.
The difference in heights of the liquid in the two sides of the manometer is 32.3 mm when the
atmospheric pressure is 765 mm Hg. Given that the density of mercury is 13.6 g/mL, the pressure of the
enclosed gas is ________ atm.
A) 1.05
B) 1.01
C) 0.976
D) 0.993
E) 1.08
5) In a Torricelli barometer, a pressure of one atmosphere supports a 760 mm column of mercury. If the
original tube containing the mercury is replaced with a tube having twice the diameter of the original, the
height of the mercury column at one atmosphere pressure is ________ mm.
A) 380
B) 760
C) 1.52 × 103
D) 4.78 × 103
E) 121
6) A sample of a gas (5.0 mol) at 1.0 atm is expanded at constant temperature from 10 L to 15 L. The final
pressure is ________ atm.
A) 1.5
B) 7.5
C) 0.67
D) 3.3
E) 15
17
7) If 50.75 g of a gas occupies 10.0 L at STP, 129.3 g of the gas will occupy ________ L at STP.
A) 3.92
B) 50.8
C) 12.9
D) 25.5
E) 5.08
8) A sample of H2 gas (12.28 g) occupies 100.0 L at 400.0 K and 2.00 atm. A sample weighing 9.49 g
occupies ________ L at 353 K and 2.00 atm.
A) 109
B) 68.2
C) 54.7
D) 147
E) 77.3
9) A sample of a gas (1.50 mol) is contained in a 15.0 L cylinder. The temperature is increased from 100 °C
to 150 °C. The ratio of final pressure to initial pressure [ ] is ________.
A) 1.50
B) 0.667
C) 0.882
D) 1.13
E) 1.00
10) A sample of a gas originally at 25 °C and 1.00 atm pressure in a 2.5 L container is subject to a pressure
of 0.85 atm and a temperature of 15 °C. The final volume of the gas is ________ L.
A) 3.0
B) 2.8
C) 2.6
D) 2.1
E) 0.38
11) A sample of a gas originally at 29 °C and 1.25 atm pressure in a 3.0 L container is allowed to contract
until the volume is 2.2 L and the temperature is 11 °C. The final pressure of the gas is ________ atm.
A) 2.9
B) 2.8
C) 1.6
D) 2.1
E) 0.38
12) The reaction of 50 mL of Cl2 gas with 50 mL of CH4 gas via the equation:
Cl2 (g) + CH4 (g) → HCl (g) + CH3Cl (g)
will produce a total of ________ mL of products if pressure and temperature are kept constant.
A) 100
B) 50
C) 200
D) 150
E) 250
13) The reaction of 100 mL of Cl2 gas with 100 mL of CH4 gas via the equation:
Cl2 (g) + CH4 (g) → HCl (g) + CH3Cl (g)
will produce a total of ________ mL of products if pressure and temperature are kept constant.
A) 100
B) 50
C) 200
D) 150
E) 250
14) The reaction of 50 mL of N2 gas with 150 mL of H2 gas to form ammonia via the equation:
N2 (g) + 3H2 (g) → 2NH3 (g)
will produce ________ mL of ammonia if pressure and temperature are kept constant.
A) 250
B) 50
C) 200
D) 150
E) 100
15) The reaction of 25 mL of N2 gas with 75 mL of H2 gas to form ammonia via the equation:
N2 (g) + 3H2 (g) → 2NH3 (g)
will produce ________ mL of ammonia if pressure and temperature are kept constant.
A) 250
B) 50
C) 200
D) 150
E) 100
16) The reaction of 50 mL of Cl2 gas with 50 mL of C2H4 gas via the equation:
Cl2 (g) + C2H4 (g) → C2H4Cl2 (g)
will produce a total of ________ mL of products if pressure and temperature are kept constant.
A) 100
B) 50
C) 25
D) 125
E) 150
17) The amount of gas that occupies 60.82 L at 31.0 °C and 367 mm Hg is ________ mol.
A) 1.18
B) 0.850
C) 894
D) 11.6
E) 0.120
18) The amount of gas that occupies 36.52 L at 68.0 °C and 672 mm Hg is ________ mol.
A) 127
B) 1.15
C) 878
D) 24.4
E) 12.7
19) The pressure of a sample of CH4 gas (6.022 g) in a 30.0 L vessel at 402 K is ________ atm.
A) 2.42
B) 6.62
C) 0.413
D) 12.4
E) 22.4
20) The temperature of a sample of CH4 gas (10.34 g) in a 50.0 L vessel at 1.33 atm is ________ °C.
A) 984
B) -195
C) 195
D) 1260
E) -1260
