Gases Practice Quiz
1. Which substance has the lowest density?
a) H2O(g)
b) H2O(l)
c) Hg(l)
d) Hg(g)
2. Pressure is the force per unit
a) volume.
b) surface area.
c) length.
d) depth.
3. If force is held constant as surface area decreases, pressure
a) remains constant.
b) decreases.
c) increases.
d) increases or decreases depending on the volume change.
4. What does the constant bombardment of gas molecules against the inside walls of a
container produce?
a) temperature
b) density
c) pressure
d) diffusion
5. Why does a can collapse when a vacuum pump removes air from the can?
a) The inside and outside forces balance out and crush the can.
b) The unbalanced outside force from atmospheric pressure crushes the can.
c) The atmosphere exerts pressure on the inside of the can and crushes it.
d) The vacuum pump creates a force that crushes the can.
6. What instrument measures atmospheric pressure?
a) barometer
b) manometer
c) vacuum pump
d) torrometer
7. A pressure of 745 mm Hg equals
a) 745 torr.
b) 1 torr.
c) 1 pascal.
d) 745 pascal.
8. Convert the pressure 0.840 atm to mm Hg.
a) 365 mm Hg
b) 437 mm Hg
c) 638 mm Hg
d) 780 mm Hg
9. Standard temperature is exactly
a) 100ºC
b) 273ºC
c) 0ºC
d) 0 Kelvin
10. Standard pressure is the pressure exerted by a column of mercury exactly:
a) 273 mm high
b) 760 mm high
c) 760 cm high
d) 1.00 m high
11. If the height of mercury in a barometer at 0 degrees Celsius is less than 760 mm Hg,
then
a) the atmospheric pressure is less than standard atmospheric pressure.
b) the atmospheric pressure is greater than standard atmospheric pressure.
c) the atmospheric pressure is equal to standard atmospheric pressure.
d) the atmospheric pressure cannot be determined.
12. If the temperature of a fixed quantity and volume of a gas changes, what also
changes?
a) pressure
b) density
c) mass
d) formula
13. If the temperature of a fixed quantity of gas decreases and the pressure remains
unchanged,
a) its volume increases.
b) its volume is unchanged.
c) its volume decreases.
d) its density decreases.
14. The pressure of a sample of helium is 2.0 atm in a 200-mL container. If the container
is compressed to 10mL without changing the temperature, what is the new pressure.
a) 200 atm
b) 0.10 atm
c) 100 atm
d) 40. atm
15. The volume of a gas is 5.0 L when the temperature is 5.0ºC. If the temperature is
increased to 10.0ºC without changing the pressure, what is the new volume?
a) 2.5 L
b) 4.8 L
c) 5.1 L
d) 10.0 L
16. The pressure of a sample of gas of constant volume is 2.0 atm at 30ºC. What is the
pressure of this sample at 20ºC?
a) 1.0 atm
b) 1.9 atm
c) 2.1 atm
d) 20. atm
17. The volume of a sample of oxygen is 300.0 mL when the pressure is 1 atm and the
temperature is 27.0ºC. At what temperature is the volume 1.00 L and the pressure 0.500
atm?
a) 22.0ºC.
b) 45.0ºC
c) 0.50 K
d) 227ºC
18. At 0.500 atm and 15.0ºC a sample of gas occupies 120.0 L. What volume does it
occupy at 0.250 atm and 10.0ºC?
a) 60 L
b) 111 L
c) 236 L
d) 480 L
19. In the equation H2 (g) + Cl2 (g) --> 2HCl(g),one volume of hydrogen yields how
many volumes of hydrogen chloride?
a) 1
b) 2
c) 3
d) 4
20. At constant temperature and pressure, gas volume is directly proportional to the
a) molar mass of the gas.
b) number of moles of gas.
c) density of the gas at STP.
d) rate of diffusion.
21. In the expression V = kn, n represents
a) the gas constant.
b) Avogadro's number.
c) the number of moles of gas
d) a constant.
22. The standard molar volume of a gas is all of the following EXCEPT
a) the volume occupied by 1 mol of gas at STP.
b) equal for all gases under the same conditions.
c) 22.4 L at STP
d) dependant upon the size of molecules.
23. The ideal gas law is equivalent to Boyle's law when
a) Avogadro's number is reached.
b) R equals zero
c) the pressure is 1 atm.
d) the number of moles and the temperature are constant.
24. What is the value of the gas constant?
a) 0.0821 L*atm/ mol*K
b) 0.0281 L*atm
c) 0.0281 L*atm/ mol*K
d) 0.0821 mol*K
25. Calculate the approximate volume of a 0.600 mol sample of gas at 15.0ºC and a
pressure of 1.10 atm.
a) 12.9 L
b) 22.4 L
c) 24.6 L
d) 129 L
26. A sample of gas at 25ºC has a volume of 11 L and exerts a pressure of 660 mm Hg.
How many moles of gas are in the sample?
a) 0.39 mol
b) 1.0 mol
c) 3.0 mol
d) 30. mol
27. In the reaction 2C + O2 (g) --> 2CO(g), what is the volume ratio of O2 to CO?
a) 1:1
b) 2:1
c) 1:2
d) 2:2
28. The equation for the complete combustion of methane is CH4 (g) + 2O2 (g) -->
2H2O(g) + CO2 (g). If 50 L of methane at STP are burned, what volume of carbon
dioxide will be produced at STP?
a) 16.6 L
b) 25 L
c) 50 L
d) 100 L
29. Chlorine is produced by the reaction 2HCl(g) --> H2 (g) + Cl2 (g). How many grams
of HCl (36.5 g/mol) must be used to produce 10 L of chlorine at STP?
a) 15.8 g
b) 30.2 g
c) 32.6 g
d) 36.5 g
----------Key---------1. (a)
2. (b)
3. (c)
4. (c)
5. (b)
6. (a)
7. (a)
8. (c)
9. (c)
10. (b)
11. (a)
12. (a)
13. (c)
14. (d)
15. (c)
16. (b)
17. (d)
18. (c)
19. (b)
20. (b)
21. (c)
22. (d)
23. (d)
24. (a)
25. (a)
26. (a)
27. (c)
28. (c)
29. (c)