Equilibrium isotope effects in aqueous systems. IV. The vapor pressures of NaBr, NaI, KF, Na2SO4, and CaCl2 solutions in H2O and D2O (0 to 900C). Vapor pressures of Na2SO4.10H2O, .10D2O, and CaCl2.2H2O, .2D2O

Solvent vapor pressure isotope effects have been measured in HOH/DOD between approximately 0 and 900C on the following electrolyte solutions: NaBr (2, 5, 7, and 9 m), NaI (4, 6, 8, and 10 m), KF (3, 6, 9, and 12 m), Na2SO4 (2 m and saturated solutions, and hydrated crystal), and CaCl2 (3, 5.5, 8, and 10 m, and hydrated crystal). Values of the isotope effects on the various excess thermodynamic properties of solution, including the osmotic and activity coefficients and the excess free energies, enthalpies, and entropies, have been extracted from least-square expressions which fit the VPIE over the entire concentration and temperature range. The results are compared with those obtained for alkali metal chloride solutions (I, II) and literature data where possible. They are discussed briefly in terms of solution structure. (U.S.)