Partial Molar Quantities

Abstract

This chapter is concerned with the very essential notion of partial molar quantities in chemical thermodynamics. During the determination of changes in thermodynamic quantities accompanying a chemical reaction, especially the Gibbs energy one, the question of the physical interpretation of the measured change is frequently asked. Actually, it is not the case when the studied reaction is one between perfect gases or when each of the reactants or products constitutes an independent phase. But, it is set up as soon as intervene species in solutions as reactants or products. The problem is overcome through the handling of partial molar quantities among which the chemical potential stands. This is exemplified by considering the reaction of dihydrogen gas with solid silver chloride to give hydrochloric acid and solid silver. Definitions, properties, and handling of the partial molar quantities are given. The chapter begins by the consideration of closed and open systems.