The MATLAB code accompanying the electronic version of this manuscript may serve as a valuable resource in an undergraduate thermodynamics course. Included with it is an instructional document on how to operate the MATLAB code itself as well as "Thermophysical Properties of Fluid Systems" by NIST reference data for thirty-four chemical species. An MS Excel template is also provided. Instructions are additionally provided for downloading and updating the analysis for additional systems. The use of MATLAB code or MS Excel presents opportunities for undergraduates to explore the characterization of phase equilibrium, to compare/contrast different chemical species, and to fully understand and appreciate the underlying assumptions of the Clausius/Clapeyron equation.