An equation of state (EOS) for the NH3-H2O system has been developed.
This EOS incorporates a highly accurate end-member EOS and on an empir
ical mixing rule. The mixing rule is based on an analogy with high ord
er contributions to the virial expansion for mixtures. Comparison with
experimental data indicates that the mixed system EOS can predict bot
h phase equilibra and volumetric properties for this binary system wit
h accuracy close to that of the experimental data from 50 degrees C an
d I bar to critical temperatures and pressures.