Calculation of the thermodynamic and transport properties of aqueous species at high pressures and temperatures: Standard partial molal properties of inorganic neutral species

Journal Article · Fri Sep 01 00:00:00 EDT 1989 · Geochimica et Cosmochimica Acta; (USA)

DOI:https://doi.org/10.1016/0016-7037(89)90341-4· OSTI ID:7170903

Shock, E L ^[1]; Helgeson, H C ^[2]; Sverjensky, D A ^[3]

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1. Washington Univ., St. Louis, MO (USA)
2. Univ. of California, Berkeley (USA)
3. Johns Hopkins Univ., Baltimore, MD (USA)

Consideration of interactions between neutral aqueous species and H{sub 2}O dipoles in terms of effective Born coefficients permits extension of the revised HKF equations of state for the standard partial molal properties of ionic species at high pressures and temperatures to include inorganic gases, acids, and other neutral aqueous species. Correlation algorithms similar to those used to estimate equation of state parameters for ions and electrolytes have also been developed for neutral aqueous species. Calculation of the standard partial molal thermodynamic properties of dissolved inorganic gases as well as other neutral aqueous species as a function of pressure and temperature indicates that the standard partial molal volume ({bar V}{sup 0}), heat capacity ({bar C}{sup 0}{sub P}), and entropy ({bar S}{sup 0}), together with the apparent standard partial molal enthalpy of formation ({Delta}{bar H}{sup 0}) of many of these species in the liquid phase minimize with increasing temperature at P{sub SAT}{sup *} and approach {infinity} at the critical point of H{sub 2}O. In the case of other neutral aqueous species such as SiO{sub 2(aq)}, {bar V}{sup 0}, {bar C}{sup 0}{sub P}, {bar S}{sup 0}, and {Delta}{bar H}{sup 0} behave as functions of temperature and pressure like those of electrolytes in the liquid phase and maximize with increasing temperature at P{sub SAT}, approaching {minus}{infinity} at the critical point of H{sub 2}O. High temperature/pressure equilibrium constants can be predicted for reactions involving a wide variety of neutral aqueous species for which few or no experimental data are available at temperatures > 25{degree}C. Present capabilities permit such predictions to be made for hydrothermal and magmatic conditions at pressures and temperatures to 5 kb and 1,000{degree}C.

• OSTI ID: 7170903
• Journal Information: Geochimica et Cosmochimica Acta; (USA), Vol. 53:9; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

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THERMODYNAMIC PROPERTIES
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ALGORITHMS
AQUEOUS SOLUTIONS
CHEMICAL REACTIONS
ENTHALPY
GEOCHEMISTRY
HIGH PRESSURE
HIGH TEMPERATURE
IONIC COMPOSITION
PRESSURE EFFECTS
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