Thermochemical polynomials in combustion chemistry

In kinetic modeling, one must calculate reverse rate constants of elementary reactions from forward rate constants. This is easily achieved from 

The equilibrium constant calculated from thermochemical polynomials [Eq. (6)] is Kp. Misidentifying with Kp can cause confusion (Golden, 1971) since = Kp only when the number of moles of products is equal to the number of moles of reactants i.e., when An = 0. When this is not the case 

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