1. Equations of state

Thermodynamics provides a number of equations linking the behavioral properties of a substance, and cannot do without experimental or theoretical data for a minimum number of these properties. Thermodynamics is therefore not a model that can be used to describe matter a priori [4] . Only when a certain amount of data is known can a complete set of values for thermodynamic properties be established, from which equilibrium conditions, for example, can be determined. If a thermodynamic system is characterized by n independent variables, the equation of state that describes its particular behavior is an algebraic expression associating n + 1 state variables. The equations of state relating pressure, volume and temperature (n + 1 ≥ 3 variables) illustrate this scheme with two (n ) independent variables, the value of the third...