Gibbs Function and the Equilibrium Constant in Terms of Activity

3 GIBBS FUNCTION AND THE EQUILIBRIUM CONSTANT IN TERMS OF ACTIVITY 

With the definition of the activity function, we could derive a general expression that relates AG of a reaction to the equilibrium constant and hence to eliminate the restrictions imposed on previous relationships. 

Applying the procedure used in Equations (9.49) through (9.51) and integrating from 

Substitution for the chemical potentials from Equation (16.1) gives 

Equation (16.23) is a general relationship for the calculation of AGm for any reaction from the value for AGm and from the activities Oa. b. and aq. We emphasize that Equation (16.23) refers to a system in which a mole of reaction occurs with no change in the activity of any reactant or product. Either the system is very large, the infinite copy model (as described in Section 9.6) or one in which we calculate the molar 

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