Re-evaluation of the Mean Activity Coefficients of Strontium Chloride in Dilute Aqueous Solutions from (10 to 60) 掳C and at 25 掳C up to the Saturated Solution Where the Molality Is 3.520 mol路kg鈥?
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- 作者：Jaakko I. Partanen
- 刊名：Journal of Chemical & Engineering Data
- 出版年：2013
- 出版时间：October 10, 2013
- 年：2013
- 卷：58
- 期：10
- 页码：2738-2747
- 全文大小：408K
- 年卷期：v.58,no.10(October 10, 2013)
- ISSN：1520-5134
文摘
In the present study, two H眉ckel equations have been determined for the calculation of the mean activity coefficients of SrCl2 in pure aqueous solutions at 25 掳C. The two-parameter equation with parameters B and b1 gives a good fit up to an ionic strength (= Im) of 2.0 mol路kg鈥?, and the three-parameter equation with parameters B, b1, and b2 is probably applicable up to the molality of the saturated solution where Im = 10.56 mol路kg鈥?. The dilute-solution parameters for SrCl2 solutions were obtained from the isopiestic data of Downes (J. Chem. Thermodyn. 1974, 6, 317鈥?23) against KCl solutions. The parameters resulted from this estimation were tested with all isopiestic and electrochemical data available in the literature for this purpose, and they proved to be reliable in these tests. The galvanic cell data measured by Longhi et al. using strontium amalgam cells (J. Chem. Thermodyn. 1975, 7, 767鈥?76) show that these parameter values apply well up to Im of 0.75 mol路kg鈥? in the temperature range of (10 to 55) 掳C and satisfactorily up to 70 掳C. For less dilute solutions at 25 掳C, new values for parameters b1 and b2 for the extended H眉ckel equation were solved from the isopiestic data of Macaskill et al. (J. Solution Chem. 1978, 7, 339鈥?47) against NaCl solutions, but the dilute-solution value for parameter B was used. These new parameter values were tested with good results with the existing electrochemical, vapor pressure, and isopiestic data. The new values seem to apply up to the molality of the saturated solution. For this reason, these values were also examined with the solubility data available in the best tables of thermodynamic properties (J. Phys. Chem. Ref. Data 1982, 11, Supplement No. 2). Reliable activity and osmotic coefficients for SrCl2 solutions can be obtained using the new H眉ckel equations. The relevant thermodynamic quantities calculated with these equations are tabulated here at rounded molalities, and the resulting values were compared to the values available in the literature tables.