Interpretation of equilibrium exchange rates for nonelementary reactions

In a system that is close to chemical equilibrium, the relaxation of each elementary step toward equilibrium obeys the linear laws of nonequilibrium thermodynamics. For a series reaction in which the concentration of the intermediate species are low or do not change with time, the relaxation can be characterized by one time constant, which can be associated with an overall equilibrium exchange rate for the overall reaction. The relationship between the overall equilibrium exchange rate and the equilibrium exchange rates of the individual steps is analogous to that between the overall conductance and the individual conductances of a network of electrical resistors in series. A numerical example is presented to show the range of validity of this relationship. Finally, a condition for the determinability of exchange rates is presented. Exchange rates are independently determinable if and only if the determinant of the matrix, whose elements are made up of squares of the inner products of the vectors that are made up of the stoichiometric coefficients of the species in the reactions, is non‐zero.