Question

25. You’re at the zoo and have a big red 3.20 L helium balloon. The barometric pressure is 790.0 mm Hg.
Then you hear the roar of a lion. Startled, you accidently release the balloon. It flies away. By the time
it reaches the clouds the atmospheric pressure is only 0.300 atm. What is the new volume of the
balloon?
a) 6.20 L b) 11.1 L c) 1.06 L d) 8.43 L
26. A gas sample is held at constant pressure. The gas occupies 3.62 L of volume when the temperature is
21.6°C. Determine the temperature at which the volume of the gas is 3.45 L.
a) 309 K b) 281 K c) 20.6 K d) 295 K
27. The temperature of a specific amount of gas in a sealed container changes from 20.0°C to 40.0°C. If the
volume remains constant, the pressure will change from 755 mmHg to ____.
a) 1510 mmHg b) 707 mmHg c) 378 mmHg d) 807 mmHg
28 If 2.10 mol of argon gas occupies a volume of 89.0 L, what volume will 2.45 mol of argon occupy under
the same conditions of temperature and pressure?
a) 76.3 L b) 104 L c) 7.30 mL d) 89.0 L
29. A gas sample has a volume of 4.50 L when the temperature is 28 oC and the pressure is 1.00 atm. What
will be the new volume of the gas when the temperature is changed to 0.0 oC and the pressure to 850 torr?
a) 0.25 L b) 3.6 L c) 0.15 L d) 4.4 L
30. A gas evolved during the fermentation of alcohol had a volume of 19.4 L at 17 °C and 746 mmHg.
How many moles of gas were collected?
a) 0.800 mol b) 1.25 mol c) 10.5 mol d) 13.6 mol
31. Which gas sample is not at STP?
a) 1.00 mole of neon at 760 mm Hg pressure and 0°F
b) 16.05 g of CH4 at 760 mm Hg pressure and 273 K
c) 83.80 g of krypton at 1.00 atm pressure and 32°F
d) 70.90 g of chlorine at 1.013 x 105 Pa and 273K
Copyright ©2019 Grand Canyon University Revised 8/18/19
32. How many liters will 20.0 g of Br2 occupy at STP?
a) 2.80 L b) 5.4 L c) 1.8 L d) 3.2 L
33. The density of a gas is measured at 1.653 g/L at 746 mmHg and 25.0 °C. What is its molar mass?
a) 41.2 g/mol b) 46.1 g/mol c) 0.0542 g/mol d) 31.2 g/mol
34. Which of the following gases has a density of 0.716 g/L at STP?
a) He b) CO2 c) CO d) CH4
35. The volume of HCl gas required to react with excess Mg metal to produce 6.82 L of hydrogen gas at
2.19 atm and 35°C is ________ L. 2 HCl (g) + Mg (s)  MgCl2 (s) + H2 (g)
a) 3.41 b) 6.82 c) 13.6 d) 4.38
36. Calculate the volume of H2(g) at 273 K and 2.00 atm that will be formed when 275 mL of 0.725 M HCl
(g) solution reacts with excess Mg to give hydrogen gas and aqueous magnesium chloride.
2 HCl (g) + Mg (s)  MgCl2 (s) + H2 (g)
a) 0.56 L b) 4.47 L c) 2.23 L d) 1.12 L
37. What is the total pressure in atmospheres in a 10.0 L vessel containing 2.50 x 10-3 mol of H2, 1.00 x 10-3
mol of He, and 3.00 x 10-4 mol of Ne at 35.0 oC?
1.10 atm
a) 2.75 x 10-2 atm b) 8.76 x 10-4 atm c) 3.80 x 10-3 atm d) 9.60 x 10-3 atm
38. A sample of natural gas contains 8.24 moles of methane, 0.421 moles of ethane, and 0.116 moles of
propane. If the total pressure of the gases is 1.23 x 103 mm Hg, what is the partial pressure of ethane?
a) 0.0775 atm b) 1.29 atm c) 0.0656 atm d) 0.0214 atm
39. Assume two cylinders at 27 °C are connected by a closed valve system. The right hand cylinder contains
3.0 L of He at 0.60 atm and the left hand cylinder contains 6.8 L of He at 2.0 atm. What is the total
pressure (in atm) when the valve is opened?
a) 2.6 atm b) 1.6 atm c) 24 atm d) 0.6 atm

Answer 1