Theoretical determination of the volume change on mixing for gaseous N2-H2, Ar-H2 and Ar-N2 at 170°K up to 100 ATM

Abstract In a previous paper we described a direct method to measure the volume chagge on mixing of gases at constant pressure. The results of the measurements on three mixtures, N 2 -H 2 , Ar-H 2 and Ar-N 2 were given. In this paper we apply to these systems the ideas of Prigogine and of Scott for liquid solutions. We calculated the excess volume for three different models. Comparison of experimental and theoretical values of the volume change on mixing shows that there is always a good qualitative agreement. Quantitatively the results are reasonable for the systems N 2 -H 2 and Ar-H 2 , but poor for Ar-N 2 .