Phase and chemical equilibrium
This chapter introduces applications of thermodynamics to chemistry, notably phase and chemical equilibrium. It covers the J. Willard Gibbs phase rule, the Clausiu-Clapeyron equation, the thermodynamics of mixing, the law of mass action, and electrochemical cells. A phase, as the term is used in thermodynamics, is a spatially homogeneous material body in a state of equilibrium characterized by certain parameters. The existence of phases is implied by the existence of equilibrium. Systems maintain states of equilibrium when kept under fixed conditions. The chapter shows that the chemical potential has the same value in each of the phases in which coexistence can occur. An ideal solution is defined as any mixture of liquids, gases, or solids that exhibits the properties. An electrochemical cell has two conductive electrodes, an anode and a cathode that are immersed in electrolytic solutions containing ions that can move freely.