Abstract
Pressure like temperature is a fundamental thermodynamic parameter which must be considered to understand natural phenomena. Volumetric information is derived from the pressure dependence of the Gibbs free energy in the equilibrium state. The solubilities of hydrophobic compounds and conformational equilibria of rotational isomers and proteins at high pressure are discussed from points of view of volume changes, partial molar volumes, and their isothermal compressibilities, all three important thermodynamic parameters due to pressure
