A generalized van der Waals equation of state VI. results with non-polar and polar molecules

✍ Scribed by R. Kohlen; F. Kohler; P. Svejda

• Publisher: Elsevier Science
• Year: 1986
• Weight: 233 KB
• Volume: 139-140
• Category: Article
• ISSN: 0378-4363
• DOI: 10.1016/0378-4363(86)90527-9

✦ Synopsis

A generalized van der Waals equation of state has been devised with a modeling of the anisotropic hard core of the molecule and assuming that the attractive van der Waals term becomes linear in density at sufficiently high densities. Corrections for non-linear density dependence have to be taken into account at medium and low densities. These corrections are near universal for non-polar substances, but change drastically with the polarity of the molecule. The temperature dependence of the attractive constant is small for spherical and for polar molecules, but becomes increasingly significant with increasing anisotropy of the molecular shape. With this equation the thermal behaviour of ethane, propane, butane, pentane, benzene, oxygen, monochlorodifluoromethane, acetonitrile, and ammonia could be correlated at subcritical temperatures within the experimental error of measurements.