12 mole of helium gas is contained in a container at S.T.P. The heat energy needed to double the pressure of the gas, keeping the volume constant (specific heat of the gas = 3 J gm−1 K−1) is
1638 J
If Pressure is doubled. temperature is doubled. Hence dT = 273K.
m=Mxn=0.5x4=2g
dU=nCVdT = mcVdT=2x3x273=1638J