1.15 Equations of State (7) S.J.T.U. Phase Transformation and Applications Approximations of the heat capacity of elemental gases at low pressure A monatomic ideal gas A diatomic ideal gas 3 Cr= Ci= 5 R R 5 Cp R Cp R 2 2 N2Cp=27.87+298×4.27×103=29.14J1molK) 实验 7 Cp =R=29.1J/(mol.K) 理论 2 02 Cp =29.32J/(mol.K) SJTU Thermodynamics of Materials Spring2010©X.J.Jin Lecture 2 First Law llPhase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2010 © X. J. Jin Lecture 2 First Law II 1.15 Equations of State (7) C R C R P V 2 5 2 3   Approximations of the heat capacity of elemental gases at low pressure A monatomic ideal gas A diatomic ideal gas C R C R P V 2 7 2 5   N2 2 7.8 7 298 4.2 7 1 0 2 9.1 4 /( ) 3 CP      J molK  29.1 /( ) 2 7 CP  R  J mol K O2 C 2 9.3 2 J /(mol K) P   实验 理论