Prediction of Some Important Regularities Using a Statistical Mechanical Equation of State

Four important known regularities for several pure substances have been described using a statistical mechanical equation of state (EOS) derived by Deiters. The equation of state depends on three temperature-independent parameters, which can be obtained from the critical constants. The studied regularities included: (i) near linearity of the reduced isothermal bulk modulus as a function of reduced pressure, (ii) the common bulk modulus point on the isotherms of the reduced bulk modulus versus reduced density, (iii) near linearity of the Zeno contour of reduced temperature against reduced density from the Boyle temperature to the triple point, and (iv) near linearity of the mean density of a saturated liquid and its equilibrium vapor as a function of temperature, called the ‘‘law of rectilinear diameter.’’ The results for several fluids have been compared to the available experimental data. The predictions are often satisfactory in the sensitive regions.