Kemija u Industriji (Nov 2006)
Jednadžbe stanja realnih plinova
Abstract
The properties of classical real gases, especially their deviations from ideal behaviour, are reviewed. After a brief overview of molecular interactions, the so-called traditional ('primitive') model is presented and shown to be applicable not only to monoatomic but also for many polyatomicclassical gases. Two-coefficient equation of state was derived by using virial theorem. The best known equation of state for real gases van der Waals equation - was derived by using canonical partition function. Among the empirical equations of state, Kamerlingh-Onnes' virial expansionwas described, as well as some equations of state frequently used in technical thermodynamics (Redlich-Kwong, Peng-Robinson and Benedict-Webb-Rubin). A review of statistical models of real gases is given. Cluster model is presented where all deviations from perfect gas behaviour are described by configuration integral. In addition, the limits of the cluster model are given. The Kirkwood's model of integral equation is also discussed. This model, unlike the Mayer's cluster model, is based on a hierarchy of radial distribution functions for many molecules. Finally, the methods of numerical simulation (Monte Carlo and molecular dynamics) are shortly reviewed