Apparent molar heat capacities and volumes of aqueous solutions of several 1:1 electrolytes at elevated temperatures

Abstract

The results of heat capacity (C p ) and density (d) measurements at 0.6 MPa and in the temperature range 298.15–373.15 K are presented for several 1:1 electrolytes in water. The flow microcalorimeter and densimeter used for these measurements were modificatons of the room-temperature designs. Data were obtained over concentrations ranging from 0.02 to 1.0 mol kg −1 (or to the solubility limit, whichever was lower). The heat capacity of a solution relative to that of water was measured with a precision of ±0.1 mJ K −1 g −1 at all temperatures. The density of a solution relative to that of water was measured with a precision of ±5 μg cm −3 . These C p and d results were used to calculate the apparent molar heat capacities, [Formula: see text], and volumes, [Formula: see text], at 298.15, 323.15, 348.15, and 373.15 K, at a constant pressure of 0.6 MPa. These results are in good agreement with available literature data.