3.2 The Functions F and G(1) S.J.T.U. Phase Transformation and Applications F:the Helmholtz free energy G:the Gibbs free energy Measures of the work required to change a system from one state to another. dU =TdS +oWrex Integrating at constant temperature Wro =AU-TAS=AU-A(TS)=A(U-TS) U-TS is defined as the Helmholtz free energy F =△F SJTU Physical Chemistry of Materials Spring2005©X.J.Jin Lecture 5 property relationPhase Transformation and Applications S. J. T. U. SJTU Physical Chemistry of Materials Spring 2005 © X. J. Jin Lecture 5 property relation 3.2 The Functions F and G (1) F: the Helmholtz free energy G: the Gibbs free energy Measures of the work required to change a system from one state to another. = +δWTdSdU rev Integrating at constant temperature TSUTSUSTUW )()( rev −Δ= Δ = Δ − Δ Δ= − U-TS is defined as the Helmholtz free energy F rev = ΔFW