5.1 THERMODYNAMIC ACTIVITY (2) S.J.T.U. Phase Transformation and Applications i No Units 三 Reference state:temperature,pressure and physical form Standard state:pressure and physical form Gas:pure gas at one atmosphere Condensed mater:pure liquid or solid under one atmosphere CdG,-G,-G=RTn人-RTna dG,-G,-G;=RTIn P=RTIna, Ideal gas P The fugacity of a condensed phase is equal to the fugacity of the vapor in equilibrium with it. The value of thermodynamic activity changes not only with pressure but also with composition. SJTU Thermodynamics of Materials Spring2008©X.J.Jin Lecture 9 electrochemistry IPhase Transformation and Applications S. J. T. U. SJTU Thermodynamics of Materials Spring 2008 © X. J. Jin Lecture 9 electrochemistry I 5.1 THERMODYNAMIC ACTIVITY (2) o i i i f f α ≡ i i i i i G G i RT ff =−= RTGGdG ln = lnα ∫ o o o i i i i i G G i RT PP =−= RTGGdG ln = lnα ∫ o o o Ideal gas No Units Reference state: temperature, pressure and physical form Standard state: pressure and physical form Gas: pure gas at one atmosphere Condensed mater: pure liquid or solid under one atmosphere The fugacity of a condensed phase is equal to the fugacity of the vapor in equilibrium with it. The value of thermodynamic activity changes not only with pressure but also with composition