| Autor: |
Oakes, Charles S., Simonson, John M., Bodnar, Robert J. |
| Zdroj: |
Journal of Solution Chemistry; September 1995, Vol. 24 Issue: 9 p897-916, 20p |
| Abstrakt: |
Relative densities of CaCl2(aq) with 0.22=ml(mol-kg-1)=6.150 were measured with vibrating- tube densimeters between 25 and 250°C and near 70 and 400 bars. Apparent molar volumes VF calculated from the measured density differences were represented with the Pitzer ioninteraction treatment, with appropriate expressions chosen for the temperature and pressure dependence of the virial coefficients of the model. It was found that the partial molar volume at infinite dilution VFo, and the second and third virial coefficients BV and CV, were necessary to represent VF near the estimated experimental uncertainty. The ionic-strength dependent ß(1)v term in the BV coefficient was included in the fit. The representation for VF has been integrated with respect to pressure to establish the pressure dependence of excess free energies over the temperature range studied. The volumetric data indicate that the logarithm of the mean ionic activity coefficient, ln ?±(CaCl2), increases by a maximum of 0.3 at 400 bars, 250°C, and 6 mol-kg-1 as compared with its value at saturation pressure. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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