Reaction Rates and Affinities

Abstract

A new definition of elementary reactions is being based upon the Marcelin‐De Donder formulation of reaction rates. Complex reactions resulting from sequences of elementary reactions are examined, under steady‐state conditions, both close to, and far from equilibrium. In the former case the over‐all rate is proportional to the over‐all affinity, while in the latter case, when all steps are far from their equilibria, the over‐all rate varies exponentially with the over‐all forward affinity. The problem of the identification of rate‐determining steps is discussed on the basis of the adopted definition of elementary reactions. Application of the treatment to the two‐step sequence A + B⇌C, C→D+E leads to a close connection with the absolute rate theory.