Thermodynamic Properties of Solutions in a Calcium Chloride–Calcium Nitrate–Water System

Abstract—New experimental data on saturated water vapor pressure are measured in the CaCl₂–Ca(NO₃)₂–H₂O system at 15–35°C (288.15–308.15 K) for nine compositions with different ratios of salts to provide a basis for calculating the activities of water in the system. The activity of water is shown to be independent of temperature within this range for all of the studied compositions. The activity of water was calculated using the binary parameters of the Pitzer–Simonson–Clegg model to determine the region of compositions for which parameters of interaction of a higher order can be ignored. The limit to the applicability of Zdanovsky’s rule is estimated for calcium chloride and calcium nitrate solutions.