physics question?

Question

A cylinder contains 270 L of hydrogen gas (H2 at 0.0 °C) and a pressure of 10 atm. How much energy is required to raise the temperature of this gas to 25°C? Units in kJ

Answer 1

Use the ideal gas law, we find the number of moles of hydrogen:
n = PV/RT = 10*270/(0.08206*273.2) = 120 (moles)
The specific heat of the ideal diatomic gas with a constant volume is: Cv = 5R/2 = 5*8.314/2 = 21 (J/mol*K)
Hence the required energy is: 120*21*25 = 63 (kJ)
Note that the pressure will greatly increase inside the cylinder.