ENTHALPIES OF DILUTION OF AQUEOUS-SOLUTIONS OF LICL, KCL, AND CSCL AT300, 325, AND 350-DEGREES-C

Dilution enthalpies, measured using isothermal flow calorimetry, are r eported for aqueous solutions of LiCl, KCl, and CsCl at 300 degrees C and 11.0 MPa, 325 degrees C and 14.8 MPa, and 350 degrees C and 17.6 M Pa. The concentration range of the chloride solutions was 0.5 to 0.02 m. Parameters for the Fitter excess Gibbs ion-interaction equation wer e determined from the fits of the experimental heat data. Equilibrium constants, enthalpy changes, entropy changes, and heat capacity change s for ion association of the chloride salts were estimated from the he at data. For all systems, the enthalpy and entropy changes were positi ve and had accelerating increases with temperature. The resulting equi librium constants show significant, but smaller, increases with temper ature.