Here, we have to find the dependence of internal energy on pressure, volume and temperature. We have, Internal energy, ΔU = mCvΔT Where, ΔT = change in temperature. ΔU = Change in internal energy. m= mass of the system. Cv = specific heat at constant volume Number of molecules in 1 gram mole is a constant for all gases. That is, if there is no change in temperature, ΔT = 0 ΔU = 0 Or the internal energy remains constant. That is, the internal energy per gram mole of an ideal gas depends only on temperature. It is independent of the pressure and volume of the gas.