The reaction analyses in the previous sections required equilibrium constants K that in turn were determined by the free energy changes AGo. Whether the reaction involves gaseous species, condensed phases, or both, the connection between K and AGo is:
AGo is independent of total pressure because it refers to reactants and products in pure, standard states at 1 atm. However, AGo is a function of temperature, mainly via the relation:
The linear temperature dependence in this equation accounts for the major portion of the variation of reaction free energy change with T. The reaction enthalpy change AHo and the reaction entropy change ASo are much less temperature-sensitive, and in many cases can be taken as constant properties of the reaction (see Sects. 9.2 and 9.3).
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