Ten Elementary Gas Law Problems (and some not so elementary ones)

Unit 7: States of Matter                                                                                Chapter 14

1.        If 4.25 mL of oxygen gas are collected at 9.80 kPa pressure, what pressure is necessary to have the gas occupy 4.85 mL, assuming that the temperature stays the same?

2.        A gas has a volume of 275 mL when first measured at a pressure of 9.80 x 10⁴ Pa.  If the temperature is left unchanged, what would the gas volume be at standard pressure?

3.        What volume will a sample of nitrogen gas occupy at 28.0^oC if the gas occupies a volume of 457 mL at 0.0^oC?  Assume that the pressure remains constant.

4.        If a gas occupies a volume of 733 mL at 10.0^oC, at what temperature (in Celcius) will it occupy a volume of 1225 mL if the pressure remains constant?

5.        Calculate the volume of an ideal gas at STP if 502 mL of the gas are collected at 29.7 ^oC and 696 mmHg.

6.        An automobile tire has a pressure of 210 kPa at 20.0^oC.  What will be the tire pressure after driving for some time if the temperature rises to 35.0^oC?

7.        The partial pressure of helium is 13.5 kPa in a mixture of helium, oxygen, and methane gases.  If the total pressure is 1.00 atm and the partial pressure of oxygen is 156 mmHg, what is the partial pressure of methane?

8.        If 0.400 L of an ideal gas is collected over water at 20.0^oC at an atmospheric pressure of 97.0 kPa, what is the volume of the dried gas at STP? (The vapor pressure of water is 2.3 kPa at 20.0^oC.)

9.        A weather balloon with a volume of 425 L leaves from the ground under 1.00 atm pressure and at 20.0^oC.  What will its volume be when it has ascended to a height where the pressure is 200. mmHg and the temperature is -50.0^oC?

10.     Two contained noble gases escape through a small hole in the container.  Knowing that the gases are helium and xenon, which gas escapes faster?  Calculate the ratio of their rates of effusion.

More Gas Law Problems: (R = 8.31 L-kPa/mol-K; 0.821 L-atm/mol-K) 

11.     How many moles of gas are present in a 25.0-L container with a pressure of 1.50 atm and measured at 17^oC?  If this sample of gas has a mass of 75.0 g, what is its molar mass?

12.     Two mischievous Chemistry students throw a 450. g block of dry ice (CO₂) into a swimming pool.  When the ice sublimes, what volume of the gas will be produced if the pressure is 775 mmHg and the temperature is 28^oC?

13.     A 12.5 g mass of CaCO₃ is decomposed and produces CO₂.  What pressure will this gas exert if it is collected in a 1.00 L container at 25.0^oC?

14.     A 10.0 g mass of krypton occupies 15.0 L at a pressure of 156 kPa.  Find the density of krypton when the pressure is increased to 215 kPa at the same temperature.  (Hints: The volume changes under the new pressure conditions.  Density is mass/volume.)

15.     What is the molar volume of a gas at 1250 mmHg pressure and 50.^oC?

16.     A balloon is attached to a monometer as in the video.  The balloon is inflated to a diameter of 18.0 cm at a temperature of 305 K.  The atmospheric pressure is 768 mmHg.  When the balloon is inflated to the level the mercury level in the manometer connected to the balloon is 1.0 cm lower than at the side open to the atmospheric pressure.  This balloon is then heated and the volume expands so that the diameter is now 19.0 cam.  The pressure also increases so that the mercury on the balloon side of the manometer reads 18.3 cm while the level open to the atmospheric pressure reads 20.7 cm.  What is the temperature inside the balloon?