PRETEST - Gas Laws Multiple Choice: 35 minute time limit
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1.
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Which of the following
gases will have the smallest rate of effusion? a) H b) He
c) N d) Ne e) CO |
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2.
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A gas mixture contains 2.0
moles of helium and 8.0 moles of carbon dioxide and is held under conditions
of standard temperature and pressure. What is the partial pressure of the
carbon dioxide? a) 2.0atm b) 0.2atm
c) 8.0atm d) 0.8 atm e) none of these |
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3.
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The temperature of a fixed
mass of gas in a rigid container is decreased from 127.00 degrees Celsius to
27.0 degrees Celsius. The initial pressure was 1000. mmHg. Which is closest
to the new pressure, in mmHg, after cooling? a) 250 b) 500
c) 750 d) 900 e) 1330 |
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4.
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A gas is collected over
water at a temperature where the vapor pressure of water is known to be 25.0
mmHg. The total pressure recorded in the container is 775.0 mmHg, what is the
pressure of the “dry” gas, in mmHg, being collected? a) 825 b) 800
c) 775 d) 750 e) 725 |
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5.
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2.00 moles of a gas are
contained in a 2.00 liter vessel at a temperature of 300. degrees Celsius at
a pressure of 10.00 atm. The gas is allowed to expand to a new volume of 8.00
liters, but at the same time maintaining the original temperature. What is
the new pressure? a) 10.0 atm b) 7.50 atm c) 5.00 atm d) 2.50 atm e) 1.25 atm |
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6.
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A gas that is confined in a
rigid container is heated. Which of the following statements is true? a) the kinetic energy of the gas particles will decrease b) the pressure will increase c) the density will decrease d) the number of moles of gas will increase e) the volume will increase |
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7.
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A gas is held under
conditions of standard temperature and pressure. It is found that 44.0 grams
of the gas occupies a volume of 22.4 L under these conditions. What is the
gas? a) CO2 b)
Cl2 c) F2 d) N2 e) O2 |
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8.
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A mixture of gases at a
constant temperature includes equal numbers of moles of each of the
following. Carbon dioxide, Helium, Neon, Oxygen and Nitrogen. Which gas has
the lowest µrms? a) He b) Ne
c) O2 d) N2 e) they all are the same |
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9.
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Under what conditions do
the assumptions associated with the application of an ideal gas hold true? a) low pressure and high temperature b) high pressure and large volume c) large volume and high temperature d) small volume and high temperature e) high pressure and low temperature |
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10. |
A gas is heated from 23.000
degrees Celsius to 127.0 degrees Celsius at a constant pressure of 10.00 atm.
If the initial volume is V, which equation will best identify the new volume? a) (20/123) ×V b) (123/20) ×V c) (296/400) ×V d) (400/296) ×V e) none of these |
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11. |
Which assumption is part of the kinetic molecular theory? a) the particles in a gas have a distinct volume
measured in mL b) the particles in a gas attract one another via
intermolecular forces c) the particles in a gas collide and emit energy to
the surroundings d) the speed of the particles in a gas is directly
proportional to the Kelvin temperature e) the particles in a gas can be compressed |
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12. |
For a substance
that remains a gas under the conditions listed, deviation from the ideal gas law would be
most pronounced at A)-100 C and
5.0 atm B) -100 C and
1.0 atm C) 0 C and 1.0
atm D) 100 C and
1.0 atm E) 100
C and 5.0 atm |
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13. |
Look at the
picture below, illustrating the volume and pressure of three separate, closed
containers, all at the same temperature:
2.0L 2.0L 1.0L 2.0atm 2.0atm 1.0atm After stopcocks
of all three containers are opened, which is closest to the pressure inside
the system (ignore the small volume of the connective capillary tubing). a) 1.0atm b) 1.5atm c) 1.8atm d) 2.0atm e) 2.2atm |
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14. |
A hot-air
balloon rises. Which is the best explanation for this observation? a) the pressure on the walls of the balloon
increases with increasing temperature b) the difference in temperature between
the air inside and outside the balloon produces convection currents c) the cooler air outside the balloon
pushes in on the walls of the balloon d) the rate of diffusion of cooler air is
less than that of warmer air e) the density inside the balloon is less
than that of the surrounding air |
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15. |
A rigid metal
tank contains helium gas. Which applies to the gas in the tank when some
helium is removed at constant temperature? a) the volume of the gas decreases b) the pressure of the gas decreases c) the average speed of the gas molecules
decreases d) the total number of gas molecules
remains the same e) the average distance between the gas
molecules decreases |
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16. |
Equal numbers
of moles of He(g), Ar(g), and Ne(g) are placed in a glass vessel at room
temperature. If the vessel has a pinhole-sized leak, which of the following
will be true regarding the relative values of the partial pressures of the
gases remaining in the vessel after some of the gas mixture has effused? a) PHe> PNe > PAr b) PAr > PNe >
PHe c) PNe > PAr >
PHe d) PAr > PHe >
PNe e) PNe = PHe =
PAr |
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17. |
Which gas
deviates LEAST from ideal behavior? a) SO2 b) Ne
c) CH4 d) N2 e) H2 |
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18. |
Approximately
what volume do 3.0 moles of Kr gas occupy at STP? a) 22.4 L b) 44.8 L c) 67.2 L d) 89.6 L e) none of the above |
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19 – 21. |
Questions 19-21 refer to
the following gases at 0˚C and 1 atm. a) Ne b) Xe c) H2 d) CO2 e) NO 19) Has an average atomic or molecular speed closest to
that of N2 molecules at 0˚C and 1atm. 20) Has the smallest density 21) Has the slowest rate of effusion through a pinhole |
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22. |
A flask contains 0.50 mole
of SO2(g), 1.50 mole of CH4(g) and 1.0mole of O2(g).
The total pressure of the gases in the flask is 1000mmHg. Which is closest to
the partial pressure of the O2 (g) in the flask? a) 800 mmHg b) 667 mmHg c) 500 mmHg d) 333 mmHg e) 160 mmHg |
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23. |
What
volume of O2(g) is required to react with excess CS2(l) to
produce 10.0L of CO2(g)? (Assume all gases are measured at 0˚C
and 1atm.) a) 30L b) 10L c) 1/3 x 22.4L d) 2 x 22.4L e) 10 x 22.4L |
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24. |
Butane gas, C4H10,
burns in excess oxygen gas. When the equation for this reaction is correctly
balanced and all coefficients are reduced to their lowest whole-number terms,
the coefficient for O2 is a) 7 b) 9 c) 13 d) 17 e) 26 |
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25. |
An 11.2L container will
hold about 8.5g of which of the following gases at 0˚C and 1atm? a) SO2 b) N2 c) CO2 d) C4H8 e) NH3 |
TallY;
Effusion/diffusion:
1, 15, 21
Gay lussac: 3
Charles: 5, 10
KMT: 6, 11, KTM,
temp relates to KE 14
PvnRT solving for
MM (ez with 22.4): 7
Vrms: 8, 19
Bulbs of gas
mixing w/ Partial pressures/Dalton: 12
density of gases,
hot air balloon: 13, 20
Deviation from
ideal gas behavior: 9, 16
Volume of gas at
STP: 18, 25 (but asked differently)
Gas stoich 23
Answers:
1) e
2)
d
3)
c
4)
d
5)
d
6)
b
7)
a
8)
c
9)
a
10)
d
11)
d
12)
a
13)
c
14)
e
15)
b
16)
b
17)
e
18)
c
19)
e
20)
c
21)
b
22)
d
23)
a
24)
c
25)
e