Calculation of the Vapor Pressure and Heats of Vaporization and Sublimation of Liquids and Soilids, Especially Below One Atmosphere Pressure. I. Ethylene

摘要

A number of thermodynamic relations are presented for computing, or assessing the probable accuracy of, the vapor pressure and heat of vaporization and sublimation of liquids and solids as a function of temperature. The relations are exact and take into account gas imperfection in the vapor phase. The solution of the equations, in general, requires iterative procedures which can be readily handled on an automatic digital computer. Applications of certain of the relations to the computation of the vapor pressure and heat of vaporization and sublimation of ethylene from its normal boiling point (169.40K) to 20K are presented. The computed results are given at 2 degree intervals from 168K to 100K and 5 degree intervals from 100K to 20K. The computed results are compared with the available experimental data. The calculated results are thermodynamically consistent with the available experimental data and represent a thermodynamically acceptable extrapolation of these data to 20K. (Author)