恒温下熵变的计算(3) S.J.T.U. Phase Transformation and Applications ar) 8.-s-fas-or) dp EX:solid the volumetric thermal expansion coefficient, =Vav For a change in pressure from 1 atm to 10 atm at constant pressure.The molar volume and volumetric thermal expansion coefficient are constant over the pressure range of interest. AS=-SVardP=-Var(P:-P)=-9Vay H SJTU Thermodynamics of Materials Spring 2006 ©X.J.Jin Lecture 6 property relation applications
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2006 © X. J. Jin Lecture 6 property relation applications 恒温下熵变的计算(3) T T P V P S ⎟⎠⎞ ⎜⎝⎛ ∂∂ ⎟ = ⎠⎞ ⎜⎝⎛ ∂∂ − ∫∫ ⎟⎠⎞ ⎜⎝⎛ ∂∂ −==− 21 21 12 PP P dP TV SdSS EX: solid the volumetric thermal expansion coefficient, For a change in pressure from 1 atm to 10 atm at constant pressure. The molar volume and volumetric thermal expansion coefficient are constant over the pressure range of interest. V V P P αV α 12 9)( VPPVdPVS α 2 1 −=Δ −=−−= ∫ αV V P P V V TV TV V α ⎟ = α ⎠⎞ ⎜⎝⎛ ∂∂ ⎟⎠⎞ ⎜⎝⎛ ∂∂ = 1
恒温下熵变的计算(4) S.J.T.U. Phase Transformation and Applications EX:copper, %,=16.7×106K-1 V=13 InV=3Inl =3 l V 1 a,=3a1 For a change in pressure from 1 atm to 10 atm at constant pressure. AS=-fVaydP=-Var(P-P)=-9PVay=-27RVay =-3.24×10-4J/mol.K) △S=-19.14J/mol.K) for an ideal gas SJTU Thermodynamics of Materials Spring 2006 ©X.J.Jin Lecture 6 property relation applications
Phase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2006 © X. J. Jin Lecture 6 property relation applications 恒温下熵变的计算(4) For a change in pressure from 1 atm to 10 atm at constant pressure. ( ) KmolJ V VPPPVdPVS V VP l P P V ×−= ⋅ −=Δ −=−=−−= − ∫ /1024.3 9)( 27 4 12 1 1 2 1 α α α α EX: copper, 16 107.16 −− αl ×= K l dl V Vd ln3ln lVlV 3 3 == = lV P T l ldT dV V αα σ 3 1 3 ⎟ = ⎠⎞ ⎜⎝⎛ ∂∂ ⎟ = ⎠⎞ ⎜⎝⎛ ΔS = − /14.19 ( ) ⋅ gasidealanforKmolJ