New Thermodynamic Paradigm of Chemical Equilibria

Abstract

The paper presents new thermodynamic paradigm of chemical equilibrium, setting forth comprehensive basics of Discrete Thermodynamics of Chemical Equilibria (DTd). Along with previous results by the author during the last decade, this work contains also some new developments of DTd. Based on the Onsager's constitutive equations, reformulated by the author thermodynamic affinity and reaction extent, and Le Chatelier's principle, DTd brings forward a notion of chemical equilibrium as a balance of internal and external thermodynamic forces (TdF), acting against a chemical system. Basic expression of DTd is the chemical system logistic map of thermodynamic states that ties together energetic characteristics of chemical reaction, occurring in the system, the system shift from "true" thermodynamic equilibrium (TdE), and causing that shift external thermodynamic forces. Solutions to the basic map are pitchfork bifurcation diagrams in coordinates "shift from TdE - growth factor (or TdF)"; points, corresponding to the system thermodynamic states, are dwelling on its branches. The diagrams feature three typical areas: true thermodynamic equilibrium and open equilibrium along the thermodynamic branch before the threshold of its stability, i.e. bifurcation point, and bifurcation area with bistability and chaotic oscillations after the point. The set of solutions makes up the chemical system domain of states. The new paradigm complies with the correspondence principle: in isolated chemical system external TdF vanish, and the basic map turns into traditional expression of chemical equilibrium via thermodynamic affinity. The theory binds together classical and contemporary thermodynamics of chemical equilibria on a unique conceptual basis. The paper is essentially reworked and refocused version of the earlier preprint on the DTd basics, supplemented with new results.