Mean molal stoichiometric activity coefficients of alkali halides and related electrolytes in hydrothermal solutions
The mean molal stoichiometric activity coefficients have been measured for NaCl at 325/sup 0/ and 350/sup 0/C and for KCl and CaCl/sub 2/ from 200/sup 0/ to 350/sup 0/C using the static vapor pressure method. Differential vapor pressure measurements made using a strain-gauge transducer proved to be rapid and accurate. The vapor pressures were converted to osmotic coefficients, and these osmotic coefficients were fit to both the Lietzke-Stoughton and Pitzer equations. Parameters for these salts and others (NaBr, NaI, NaHS, KBr, KI, LiCl, LiBr, and LiI), for which literature data exist, were tabulated. Many of the trends in the calculated activity coefficients can be correlated with respect to the effect of the ions on the structure of the water. A simple model is presented that factors the activity coefficient into three parts corresponding to long-range electrostatic ion-ion interactions, hydration, and association: this reproduces experimental values with reasonable accuracy. The authors demonstrate a correlation between the ionic potential ratio, (Z/sub c//r/sub c/)/(Z/sub a//r/sub a/), and the activity coefficient, which corresponds physical to the structure-making/breaking correlation. The model has been applied qualitatively to the high temperature data obtained here. The model has also been used to reevaluate the MacInnes convention as a means of obtaining single-ion activity coefficients.
- Research Organization:
- Princeton Univ., NJ
- OSTI ID:
- 6465153
- Journal Information:
- Am. J. Sci.; (United States), Vol. 284:6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GEOTHERMAL FLUIDS
STOICHIOMETRY
CALCIUM CHLORIDES
LITHIUM BROMIDES
LITHIUM CHLORIDES
LITHIUM IODIDES
POTASSIUM BROMIDES
POTASSIUM CHLORIDES
POTASSIUM IODIDES
SODIUM BROMIDES
SODIUM CHLORIDES
SODIUM IODIDES
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
BROMIDES
BROMINE COMPOUNDS
CALCIUM COMPOUNDS
CALCIUM HALIDES
CHLORIDES
CHLORINE COMPOUNDS
FLUIDS
HALIDES
HALOGEN COMPOUNDS
INORGANIC PHOSPHORS
IODIDES
IODINE COMPOUNDS
LITHIUM COMPOUNDS
LITHIUM HALIDES
PHOSPHORS
POTASSIUM COMPOUNDS
SODIUM COMPOUNDS
152001* - Geothermal Data & Theory- Properties of Aqueous Solutions