advertisement

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