The molar enthalpies of solution and vapour pressures of saturated aqueous solutions of some cesium salts

Vapour pressures of water over saturated solutions of cesium chloride, cesium bromide, cesium nitrate, cesium sulfate, cesium formate, and cesium oxalate were determined as a function of temperature. These vapour pressures were used to evaluate the water activities, osmotic coefficients and molar enthalpies of vapourization. Molar enthalpies of solution of cesium chloride, Δ_solH_m(T = 295.73 K; m = 0.0622 mol • kg ^-1) = (17.83 ± 0.50) kJ • mol^-1; cesium bromide, Δ_solH_m(T = 293.99 K; m = 0.0238 mol • kg^-1) = (26.91 ± 0.59) kJ • mol^-1; cesium nitrate, Δ_solH_m(T = 294.68 K; m = 0.0258 mol • kg^-1) = (37.1 ± 2.3) kJ • mol^-1; cesium sulfate, Δ_solH_m(T = 296.43 K; m = 0.0284 mol • kg^-1) = (16.94 ± 0.43) kJ • mol^-1; cesium formate, Δ_solH_m(T = 295.64 K; m = 0.0283 mol • kg^-1) = (11.10 ± 0.26) kJ • mol^-1 and Δ_solH_m(T = 292.64 K; m = 0.0577 mol • kg ^-1) = (11.56 ± 0.56) kJ • mol^-1; and cesium oxalate, Δ_solH_m(T = 291.34 K; m = 0.0143 mol • kg^-1) = (22.07 ± 0.16) kJ • mol^-1 were determined calorimetrically. The purity of the chemicals was generally greater than 0.99 mass fraction, except for HCOOCs and (COOCs)₂ where purities were approximately 0.95 and 0.97 mass fraction, respectively. The uncertainties are one standard deviations.