Definition of electro-chemical potential of the substance:
where
x .. mole fraction of the substance in the solution
T .. temperature in Kelvins
v .. eletric potential of the solution
z .. elementary charge of the substance (like -1 for electron, +2 for Ca^2+)
R .. gas constant
F .. Faraday constant
gamma .. activity coefficient
u°(T) .. chemical potential of pure substance
DfG(T) .. free Gibbs energy of formation of the substance at current temperature T.
DfH .. free enthalpy of formation of the substance
DfS .. free entropy of formation of the substance
Be carefull, DfS is not the same as absolute entropy of the substance S° from III. thermodinamic law! It must be calculated from tabulated value of DfG(298.15 K) and DfH as DfS=(DfH - DfG)/298.15.
2015
Marek Matejak, Charles University, Prague, Czech Republic