Author :
Parsafar, Gholamabbas,Mason, E. A
Abstract :
A general regularity has been found for dense fluids, both compressed liquids and dense supercritical fluids, namely, that (Z - 1)v**2 varies linearly with respect to p**2, where Z = pv/RT is the compression factor and p = 1/v is the molar density. The regularity is tested with experimental data for 13 fluids (Ar, N***2, O***2, CO, CH***4, C***2H***6, C***3H***8, C***2H***4, C***2H***2, C***6H***6, CH***3OH, NH***3, H***2). It is shown to be compatible with equations of state based on statistical-mechanical theory, although the latter do not predict as great a range of linearity as is suggested by experiment. The regularity holds experimentally for densities greater than the Boyle density and for temperatures below about twice the Boyle temperature. The upper density limit is less certain but seems to be the freezing line for liquids (T < T***c)and at least about twice the Boyle density for supercritical fluids. The temperature dependences of the intercept and slope of the linearity are predicted from a simple model and are in good agreement with experiment.
