Thermodynamic excess functions of mixtures of simple molecules according to several equations of state

Abstract

We had previously shown that the thermodynamic properties of mixtures of simple molecules agree well with experiment when they are calculated by using van der Waals's, or better Guggenheim's, equation of state as the basis of the “one-fluid theory” of mixtures together with van der Waals's original “one-fluid relations”. We have now made a similar comparison using the “two-fluid theory”, and also using the one-fluid theory, for each of seven equations of state (including the two used before) all of which have been discussed recently in connection with pure hard-sphere liquids. The two-fluid theory gives a better overall account of the experimental results than the one-fluid theory especially for the excess volumes. Of the seven equations of state, van der Waals's equation gives the least good overall fit; there is little to choose among the other six.