Abstract
The initial thermoelectric power, epsilon/sub theta/, of the cell Ag/AgCl/KCl/AgCl/Ag has been measured from 30 to 90/sup 0/C at KCl molalities of 0.01, 0.005, and 0.001 m. The temperature dependence of epsilon/sub theta/ is consistent with other workers' results, obtained at lower temperatures or higher concentrations, and can be used to establish an absolute or single-ion heat capacity scale, providing the indeterminate single-ion Eastman entropy and heat capacity of transport, S/sup 0/(Cl/sup -/,25/sup 0/C) and C/sub p//sup 0/(Cl/sup -/), can be estimated. Application of the Eastman-Agar expression for the concentration dependence of epsilon/sub theta/ suggests that C/sub p//sup 0/(Cl/sup -/) greater than or equal to C/sub p//sup 0/(KCl)/2. Our epsilon/sub theta/ data, combined with literature values for S/sup 0/(KCl) and C/sub p//sup 0/(KCl), yield a self-consistent ionic scale, s/sup 0/(H/sup +/,25/sup 0/C) = 19.4 +- 2.5 J K/sup -1/mol/sup -1/ and c/sub p//sup 0/(H/sup +/,25/sup 0/C) greater than or equal to -57 J K/sup -1/mol/sup -1/. A more speculative argument, based on the assumption that S/sup 0/(Cl/sup -1/) approx. = S/sup 0/(K/sup +/) at high temperature due to similarities in the secondary waters of hydration and Stokes radii of each ion, suggests that c/sub p//sup 0/(H/sup +/,25/sup 0/C) less thanmore » or equal to 13 J K/sup -1/mol/sup -1/. 5 figures, 1 table.« less
Published Version
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