A general equation of state for dense fluids

A general equation of state, originally proposed lbr compressed solids by Parsafar and Mason, has been successfully applied to dense fluids. The equation was tested with experimental data for 13 fluids, including polar, nonpolar, saturated and unsaturated hydrocarbons, strongly hydrogen bonded, and quantum fluids. This equation works well Ibr densities larger than tile Boyle density Pn [ I/Ih~ = Tl~ dB2( Tu~)/dT, where B q Ti3) is the second virial coelficient at the Boyle temperature, at which B_, = 0] and for a wide temperature range, specifically from the triple point to the highest temperature fc, r which the experimental measurements have been reported. The equation is used to predict some important known regularities for dense fluids, like the comrnon bulk modulus and the common compression points, and the Tait Murnaghan equation. Regarding tile common points, the equation of state predicts that such common points are only a low-temperature characteristic of dense fluids, as verified experimentally. It is also Iimnd that the temperature dependence of tile parameters of the equation of state diflers from those given for tile compressed solids. Specilical[y they are given by A,(T) = a, + b, T+ c, Tʹ- - d, T In(T).