Thermodynamic Properties for Argon

An analytical equation of state is applied to calculate the thermodynamic properties for argon. The equation of state is that of Song and Mason. It is based on a statistical-mechanical perturbation theory of hard convex bodies and can be written as fifth-order polynomial in the density. There exist three temperaturedependent parameters: the second virial coefficient, an effective molecular volume, and a scaling factor for the average contact pair distribution function of hard convex bodies. We used Lennard-Jones (12-6) potential for calculation temperature-dependent parameters. The equation of state has been applied to calculate thermodynamic properties including the internal energy, the enthalpy, the entropy, the heat capacity at constant pressure, and the speed of sound for argon. The theoretical results are in good agreement with the experimental data.