Gas Law unit review questions
1.
A 32.0 mL sample of hydrogen is collected over water at 20.oC and
750.0 torr. What is the volume of the dry gas at STP? (Vapor pressure
of water at 20 oC = 17.5 torr). How many moles of Hydrogen gas is this?
0.029 L
0.0013 mol
2. If I initially have a gas at a pressure of 12 atm, a volume of 23 liters, and a
temperature of 200 K, and then I raise the pressure to 14 atm and increase
the temperature to 300 K, what is the new volume of the gas? 30.5 L
3. A gas that has a volume of 28 liters, a temperature of 45° C, and an unknown
pressure has its volume increased to 34 liters and its temperature decreased
to 35° C. If I measure the pressure after the change to be 2.0 atm, what was
the original pressure of the gas? 2.51 atm
4. If I have 4 moles of a gas at a pressure of 5.6 atm and a volume of 12 liters,
what is the temperature?
205K
5. If I have 0.275 moles of a gas at a temperature of 75 K and a pressure of 1.75
atm, what is the volume of the gas?
0.97L
6. The density of a gas is 1.26 g/L at STP. What is the mass of 1 mole?
1 mole = 28.64 g
7. What could this gas be?
Most likely is it Nitrogen (N2)
8. If I have two containers of gases. One contains Krypton, the other contains an
unknown gas. I open equal size holes in each container and find that the
unknown gas effuses at a rate that is 1.45 times as fast as the Krypton. What
is the unknown gas?
Argon
Use the following equation for the remaining questions:
2C8H18(l) + 25O2(g)  16CO2(g) + 18H2O(g)
This is the reaction of gasoline (octane) and Oxygen in internal combustion
engines.
9. If 4.00 moles of gasoline are burned, what volume of Oxygen is needed if the
pressure is 0.953 atm and the temperature is 35.0° C?
1330 L Oxygen
10. How many liters of Oxygen would be needed to produce 45.0 L of Carbon
Dioxide is the temperature and pressure for both are 0.00° C and 5.02 atm?
70.3 L