Name:    Practice Test - Gas Laws

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.

1.

Convert 82.1 kPa to mm Hg. (1 atm = 760 mm Hg = 101.325 kPa)
 a. 0.810 mm Hg b. 10.9 mm Hg c. 616 mm Hg d. 2.40 x 103 mm Hg e. 6.32 x 106 mm Hg

2.

At constant temperature, 14.0 L of O2 at 0.882 atm is compressed to 1.75 L. What is the final pressure of O2?
 a. 0.111 atm b. 0.142 atm c. 7.06 atm d. 21.6 atm e. 27.8 atm

3.

The lid is tightly sealed on a rigid flask containing 3.50 L H2 at 17 °C and 0.913 atm. If the flask is heated to 71 °C, what is the pressure in the flask?
 a. 0.770 atm b. 1.08 atm c. 2.95 atm d. 3.81 atm e. 13.3 atm

4.

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

5.

A 0.225-L flask contains CH4 at 27 °C and 318 mm Hg. What is the pressure of the CH4 if the volume is increased to 0.500 L and the temperature increased to 95 °C?
 a. 117 mm Hg b. 176 mm Hg c. 503 mm Hg d. 508 mm Hg e. 867 mm Hg

6.

If a 3.44-L flask of SO2 at 1.65 atm contains the same number of molecules as a 5.00-L flask of H2 at -7 °C and 1.00 atm, what is the temperature (in °C) of the SO2?
 a. -39 °C b. 29 °C c. 88 °C d. 249 °C e. 575 °C

7.

The pressure in a 20.0 L flask is 0.512 atm at 72 °C. How many moles of gas are in the flask? (R = 0.08206 L·atm/mol·K)
 a. 0.0297 mol b. 0.142 mol c. 0.276 mol d. 0.362 mol e. 1.73 mol

8.

A 50.0 L cylinder of Ar has a pressure of 137 atm at 25 °C. What mass of Ar is inside the cylinder? (R = 0.08206 L·atm/mol·K)
 a. 0.143 g b. 4.48 g c. 918 g d. 2.80 x 102 g e. 1.12 x 104 g

9.

What volume is occupied by 8.50 g C2H2 at STP (standard temperature and pressure)? (R = 0.08206 L·atm/mol·K)
 a. 0.670 L b. 7.31 L c. 7.98 L d. 68.7 L e. 191 L

10.

At 453 K and 755 mm Hg, what volume of N2 will react completely with 22.2 L H2 to produce NH3?
N2(g) + 3 H2(g) 2 NH3(g)
 a. 12.4 L b. 14.8 L c. 22.2 L d. 44.4 L e. 66.6 L

11.

What volume of O2, measured at 91.2 °C and 743 mm Hg, will be produced by the decomposition of 4.88 g KClO3? (R = 0.08206 L·atm/mol·K)

2 KClO3(s) → 2 KCl(s) + 3 O2(g)
 a. 0.305 L b. 1.22 L c. 1.83 L d. 24.0 L e. 37.4 L

12.

What volume of O2(g), measured at 17.7 °C and 0.978 atm reacts with 15.1 g C4H10 to produce CO2(g) and H2O(l)? (R = 0.08206 L·atm/mol·K)
 a. 2.51 L b. 6.34 L c. 23.5 L d. 41.2 L e. 239 L

13.

Ammonia gas is synthesized according to the balanced equation below.

N2(g) + 3 H2(g) 2 NH3(g)

If 2.75 L N2 react with 7.75 L H2, what is the theoretical yield (in liters) of NH3? 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

14.

Hydrochloric acid reacts with zinc to produce hydrogen gas according to the reaction below.

2 HCl(aq) + Zn(s) → ZnCl2(aq) + H2(g)

If 750.0 mL of 0.250 M HCl is combined with 5.98 g Zn, what volume of dry hydrogen gas can be produced? Assume the temperature and pressure of the gas are 25 °C and 742 mm Hg, respectively. (R = 0.08206 L·atm/mol·K)
 a. 1.97 L b. 2.29 L c. 2.35 L d. 4.58 L e. 4.70 L

15.

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. C2H4 b. C3H6 c. C4H8 d. C5H10 e. C6H12

16.

Carbon monoxide reacts with oxygen to form carbon dioxide.

2 CO(g) + O2(g) → 2 CO2(g)

In a 1.00 L flask, 2.40 atm of CO reacts with 4.50 atm of O2. 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

17.

Place the following gases in order of increasing average velocity at 325 K: Ar, Ne, N2, and SO2.
 a. Ar < Ne < N2 < SO2 b. Ne < Ar < N2 < SO2 c. N2 < SO2 < Ne < Ar d. SO2 < Ar < N2 < Ne e. Ar = Ne = N2 = SO2

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.

How long will it take 10.0 mL of Cl2 gas to effuse through a porous barrier if it has been observed that 76.3 minutes are required for 10.0 mL of HCl gas to effuse through the same barrier?
 a. 54.7 min. b. 106 min. c. 148 min. d. 202 min. e. 289 min.

20.

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