Chapter 7 - Activity

Abstract

Frist, we introduced and defined the activity coefficient and listing the chemical potential expressions for constituents of ideal mixtures, and ideal dilute solutions of nonelectrolytes. These led to observe a common general expression for chemical potential. A general formula for the real chemical potential was written. The activity coefficient has different symbols based on the reference state. We determined the activity coefficient based on fugacity and Henry's law for the constituents of liquid mixtures, solutes, solvents in which a pure liquid is the reference state. A definition of activity was given, and how it relates to the activity coefficient, fugacity, Henry constant, and pressure factor. The quantities of pressure factors in case of a constituent i in reference state, standard state, and if the reference state is the same as standard state are explored. Appropriate expression for the dependence of the pressure factor on pressure assuming incompressible volume for pure gas component, pure liquids or solids, constituents of gas mixtures, nonelectrolyte constituents of liquid or solid mixtures, solutes, and solvents at infinite dilution were determined. Expressions for the chemical potential, activity coefficient, activity, pressure factor for pure gases, gas mixtures, pure liquids or solids, nonelectrolyte liquid or solid mixtures, nonelectrolyte solutes and solvents, electrolyte solutions, single ions, symmetric electrolytes, nonsymmetrical electrolytes, individual ion of a binary solution, strong electrolyte substances were studied in detail.