A vessel of volume 0.2 m³ contains nitrogen at 1.013 bar and 15°C. If 0.2 kg of nitrogen is now pumped into the vessel, calculate the new pressure when the vessel has returned to its initial temperature. The molecular weight of nitrogen is 28, and it may be assumed to be a perfect gas.

A container holds 75.2 liters of Oxygen at 271.4K and a pressure of 3.87 atmospheres.  How much heat is required to raise the temperature of this gas to 296.4K, holding the volume constant?  Give your answer in kJ.  Treat the gas as an ideal gas.  Note:  It is understood that your answer is in units of kilo-Joules, however do not explicitly include units in your answer.  Enter only a number.  If you do enter a unit ("kJ" in this case), you answer will be counted wrong.

A closed assembly contains 2lg of air at an initial pressure and a temperature of 140 kpa and 210 celcius. If the volume  of the system is doubled and the temperature drops to 37 celcius determine the final pressure of air.