理想气体的U和H S.J.T.U. Phase Transformation and Applications To prove the enthalpy of an ideal gas is independent of pressure at constant temperature. dH=TdS+VdP as av at For an ideal gas. PV=RT 理想气体的U和H只是温度的函数，这可以应 用Maxwell关系式加以论证 〔0-北-g-业=0 aU 0 =0 av SJTU Thermodynamics of Materials Spring 2010 ©X.J.Jin Lecture 6 Property Relation llPhase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2010 © X. J. Jin Lecture 6 Property Relation II 理想气体的U和H For an ideal gas. T T T P V V V T P S T P H d H TdS VdP                               To prove the enthalpy of an ideal gas is independent of pressure at constant temperature. T T P V P S                   PV  RT       0        V V P R V T P H T   0        P T H  0           T V U 理想气体的U和H只是温度的函数，这可以应 用Maxwell关系式加以论证