The PVT Surface for Isotopomer Pairs

Extensive PVT data as well as precise values for critical property IE s are available for 3He/4He, CH4/CD4, H2/D2 and H20/D20 and these isotopomer pairs comprise an excellent reference in formulating EOS analysis of PVT IE s. Critical properties and critical property IE s for these and a few other selected isotopomer 

13 Reduced Equations of State Critical Property Isotope Effects 

Some other pairsb c6h6/c6d6 (CH3)2CO/(CD3)2CO CH3OH/CH3OD HC1/DC1 

The effect of isotopic substitution on the vapor pressure and molar volume of the reference pairs is shown schematically in Fig. 13.2. P(D20) P(H20) at low temperature, but as T increases the curves eventually cross, and P(H20) P(D20) when the VP curve ends for D20 at its critical point (21.7 MPa, 643.9 K). The critical point for H20 is at higher pressure and temperature (22.1 MPa, 647.1 K, 

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