Redlich-Kwong equation of state:

In addition to knowing the temperature, pressure, and composition (which are set by the application) we need the Redlich - Kwong parameters a and b, which require the critical temperature and critical pressure.

Enthalpy calculations:

Data needed (beyond knowing T, p, composition):

Ideal gas heat capacity formula for each chemical

Fugacity calculations

Fugacity of Pure Components:

The program uses the Chao-Seader-Grayson-Streed correlation. Function is given as specified function of reduced temperature and reduced pressure. One function is valid for hydrogen and methane, another function is valid for everything else. The accentric factor, critical temperature and critical pressure of each component must be specified.

Activity Coefficient :

Regular solution theory by Scatchard-Hildebrand

Best for: non-polar compounds, or compounds with similar molecular weights.

May work for: weakly polar compounds.