Partial molal volumes in high-temperature water. Part III. Halide and oxyanion salts

Abstract

Precise densities of aqueous solutions up to 200°, and derived limiting partial molal volumes, ϕ;°, are reported for the salts KF, KBr, Kl, KNO₃, K₂SO₄, Na₂SO₄, NH₄Cl, and NH₄ClO₄. It is possible to make a linear correspondence graph for ϕ°_ion(t) against ϕ°_ion(25°) at each temperature, for simple ions by choice of a particular value for the partial molal volume of the chloride ion ϕ°_Cl(t). Sodium and magnesium ions and oxyanions have a different temperature behaviour. The changes in ϕ° with temperature above about 100° can be correlated with changes in the molal volume of water, to give information on ion solvation, and provide a means of estimating high-temperature molal volumes.