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.