A low-parameter description of aqueous nonelectrolytes in a wide range of parameters of state

An approach is proposed for the description of the thermodynamic properties of geochemically important aqueous nonelectrolyte solutions (CO2, H2S, H-2 , CH4, O-2, and N-2). It is based on the "precise" multiparameter equation of Hill [1] for the solvent (H2O) and an expression similar to the virial e quation of state. The model includes only three individual empirical parame ters, which can be determined from the temperature dependency of Henry's co nstant. The knowledge of the thermodynamics of pure gas allows us to calcul ate the limiting thermodynamic properties of a dissolved component (chemica l potential, entropy, partial volume, and heat capacity) in a wide range of temperature (0-600 degreesC) and pressure (1-2000 bar), including the near -critical region. It was shown that such an approach could be used to estim ate the concentrational thermodynamic properties of dissolved nonelectrolyt es.