Comparison of the compressibility coefficient versus temperature, pressure, chemical potential dependencies for water and argon based on the principle of corresponding states

The application of the entropy-driven and density-driven phase transitions for analysis of phase diagram of water and argon is discussed. The reduced coefficient of isothermal compressibility is evaluated as βr = –(dV/dP)T(Pc/Vc) (Pc and Vc are the values in the critical point). The data are presented as dependencies of βr on the reduced temperature T/Tc, pressure P/Pc, and chemical potential μ/μc. Consideration is based on the principle of corresponding states. For water, the regions with anomalous behavior associated with the entropy-driven liquid–hexagonal ice phase transition and minima observed at T = (315.3 ± 0.2) K, P = (8.30 ± 0.04) kPa, and μ = (1122 ± 5) kJ/kg. For water, the baric dependence βr(P/Pc) along the liquid–vapor equilibrium line forms a closed loop with line of the liquid–hexagonal ice equilibrium. The thermodynamic similarity of water and argon is observed at relatively large temperatures T/Tc > 0.56, pressures P/Pc > 0.00358, and chemical potentials μ/μc > 0.505.