Nonequilibrium as a source of nonideality in chemical reacting systems

Abstract

The statistical theory of solutions which provides a relation between chemical potentials and the composition fluctuations is extended to the nonequilibrium chemical reacting systems. The chemical potentials in nonequilibrium reacting systems are shown to be dependent not only on the concentrations, but possibly also explicitly on the nonequilibrium constraints acting on the system. Such dependence of chemical potentials on the nonequilibrium constraints may give the system a nonideal behavior, even though it was ideal at equilibrium. To characterize the dependence of nonidealities on the nonequilibrium extent, a nonequilibrium activity coefficient is formally defined and the quantitative dependences of nonequilibrium chemical potential and activity coefficient on the nonequilibrium extent are given for a simple reaction scheme. Some implications of such dependence to the chemical reaction and diffusion processes are discussed.