Chemical Equilibrium from the Viewpoint of Mixing Entropy and Some Comments on Equilibrium Constants

Abstract

Chemical reaction equilibrium was often introduced based on the kinetic assumption called the mass action law. In this paper, problems in the kinetic concept are pointed out and several equilibrium constants are derived on the concept of thermodynamic balance using chemical potential. Points to note in the pressure dependence of several equilibrium constants are emphasized. An important relationship between the reaction quotient and the entropy of mixing and the importance of sigmoidal characteristics of equilibrium are comprehensively introduced. Comments on steady-state current–potential curves in reversible multiple electron transfer reactions are also detailed.

Keywords

• thermodynamic equilibrium
• reaction quotient
• mixing entropy
• sigmoidal characteristics