Hope College Department of Physics and Engineering Research Experiences for Undergraduates Summer 2006 Project Summary

Equations of state (EOS) are used to relate temperature, pressure, and molar volume or density. One category is cubic EOS, which can be written as cubic polynomials in a volume or density variable. The goal of this project was to generalize methods previously developed to predict equilibrium properties (density and pressure) for two specific cubic EOS, Peng-Robinson (PR) and Soave-Redlich-Kwong (SRK). The approach taken was to write a mathematical form for a general cubic EOS which included assignable parameters. The evaluation of partial derivatives with respect to temperature and to density was simplified by working with a two term pressure expression in which each term was the product of a density dependent factor and a temperature dependent factor. Once these partial derivatives were determined for the generalized equation, the assignable parameters could be substituted, and existing methods for writing equilibrium properties as series in a temperature variable could be applied.

*This material is based upon work supported by the National Science Foundation under NSF-REU Grant No. 0452206