• # question_answer 743 J of heat energy is added to raise the temperature of 5 mole of an ideal gas by 2 K at constant pressure. How much heat energy is required to raise the temperature of the same mass of the gas by 2 K at constant volume? A) 826 J B) 743 J C) 660 J D)  620 J

 [c] For constant pressure process, ${{Q}_{1}}=n{{C}_{p}}dT-nRdT$ ${{Q}_{2}}=n{{C}_{v}}dT=n({{C}_{p}}-R)dT=n{{C}_{p}}dT-nRdT$ ${{Q}_{2}}=743-5\times 8.3\times 2=660\,J$