Some Reversible Thermodynamic Relationships at Equilibrium

We shall review the derivation of two important thermodynamic relationships required for the next Chapter. These are the Poynting relation and the Clapeyron equation. They are required to derive the effects of temperature and hydrostatic pressure upon the vapor pressure of a liquid or its solid phase. From the relationships between vapor pressure and hydrostatic pressure applied to the liquid and its solid, and the relationships between vapor pressure and temperature of the liquid and its solid, we shall then derive the effects of hydrostatic pressure on melting and boiling temperatures in Chapter III. In Chapter II, we shall also review the application of thermodynamic principles to the treatment of a solution of solute in a solvent and then discuss the limitations of thermodynamic statements for interpreting the basic effect of the solute upon the solvent. This will lead to a discussion in Chapter IV of the alternatives for elucidating the essential features of solute-solvent interaction which induce the colligative properties of real solutions. For a more thorough review of chemical thermodynamics, the student should refer to current textbooks on the subject.