The apparent molar heat capacities and volumes of aqueous NaCl from 0.01 to 3 mol kg?1 in the temperature range 274.65 to 318.15 K

The heat capacities per unit volume of aqueous solutions of NaCl were measured with a flow microcalorimeter. The molality and temperature range covered were 0.01 to 3 mol kg^?1 and 274.65 to 318.15 K. The derived apparent molar heat capacities C₂, φ, when extrapolated to infinite dilution, give standard partial molar heat capacities C₂^o which are in excellent agreement with those of Criss and Cobble. The excess apparent molar heat capacities (C₂, φ - C₂^o) can be used to predict the temperature dependence of (H₂, φ - H₂^o), the excess apparent molar enthalpy. The calculated values of ΔH₂, φ agree within experimental uncertainty with the integral enthalpies of dilution of Ensor and Anderson and of Messikomer and Wood up to 323.15 K. Above this temperature significant differences are observed. The densities of the solutions were also remeasured in the same range of temperature and molality with a flow densimeter, and the derived apparent molar volumes agree with the literature values.