If for an ideal gas, the ratio of pressure and volume is constant and is equal to 1 atm L-1, the molar heat capacity at constant pressure would be

By definitionH = E + PVdHdTP=dEdTP++PdVdTP=Cp,mFor the given ideal gas, we will have PV = RT or  V2=RT  or  2VdVdTP=R or  dVdTP=R2VE=3RT2 or dEdTP=32R=Cv,mCp,m=32R+P×R2V=32+12R=2R