Molar Heat Capacities of Aqueous Ions

When the heat of solution of an electrolyte in water to form a dilute solution is measured calorimetrically at several temperatures, the standard partial molar (constant pressure) heat capacity of the electrolyte, Cpe , is obtained from the temperature coefficient of these heats, extrapolated to infinite dilution. Alternatively, the difference between the specific heat of a dilute solution of the electrolyte and that of water is obtained by flow microcalorimetry to yield the same quantity. Accurate density data at the appropriate temperature are required for the use of this technique. A recent description of the methods available for the determination of the heat capacities of aqueous electrolytes is presented by Hakin and Bhuiyan (2010). Such determinations are accurate to 1 to 4 J mol (Hepler and Hovey 1996) 

Criss and MiUero (1996,1999) used the Pitzer formulation for activity coefficients (Pitzer and Mayoraga 1973) and presented the needed electrolyte specific parameters 

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