The Thermal Temperature Coefficient of the Calomel Electrode Potential Between 0° and 70°C: II Thermodynamic Results—The Moving and Transport Entropies and Heat Capacities of Aqueous Chloride Salines and Their Ions

Abstract

The initial thermal temperature coefficient of the calomel electrode reported in Part I is combined with the results of thermal diffusion studies elsewhere to yield information about: the entropy of transport S* of the aqueous electrolytes , , , , and the experimentally determinable moving (transported) entropy the ion constituents Cl− K+ Na +, Lib+, H+, and Ca+ +. A four‐constant equation analogous to the Fuoss‐Onsager conductance equation is developed for the concentration dependence of the entropy of transport S* and is applied to the salts and . The division of the moving entropy into its nonmeasurable ionic component terms: the ionic transport entropy S* and the stationary entropy , is attempted via two postulates: the Agar postulate and the ‐bridge postulate which give results mutually consistent within about 0.8 eu (35 µVF/deg), e.g., from our data under the Agar postulate, and −4.42 eu under the ‐bridge postulate. These values are in good agreement with previously reported values of −4.48, −5.5, and −5.7 based on a number of alternative postulates. Values are also obtained for the transport heat capacity C* of the electrolytes and for the measurable moving heat capacity of the ion constituents at 30°. A division of into its nonmeasurable ionic components: C* and is also carried out on the basis of Fales and Mudge's hydrogen thermal emf data via the ‐bridge postulate, and yields, e.g., ; ; .