Calcium Nitrate. IV. Heats of Dilution of Solutions of Calcium Nitrate in Water

Thermodynamic Properties and Phase Equilibria in the H2O–Ca(NO3)2 System

“…Since, as mentioned above, the H 2 O–Ca­(NO 3 ) 2 system is prone to the formation of supersaturated solutions, some authors ,, managed to study the heats of dilution from very high concentrations. For example, Ewing and Rogers measured the integral heats of infinite dilution at 298.15 K for a series of compositions with a maximum concentration of x = 0.260, while for a saturated solution this value is x = 0.133.…”

“…This table is currently available in the online database “Thermal Constants of Substances” . We used this information in our work along with information from other sources at 298.15 K. ,− …”

Thermodynamic properties of aqueous calcium nitrate {Ca ( NO3)2}to the temperature 373 K including new enthalpy of dilution data

“…(41) Plake's vapor-pressure data have been converted to osmotic coefficients using the procedure of Rard and Platford. (42) Prior to the measurements made as part of this study, dil H data were limited to T = 298.15 K. The low molality data of Lange and Streeck (9) are relatively straightforward, while the higher molality data of Ewing and Rogers (8) were graphically adjusted and values of dil H taken from the resultant graphs. The data from Lange and Streeck and those from this study are shown in figure 1.…”

“…The data from Lange and Streeck and those from this study are shown in figure 1. The data of Ewing and Rogers (8) have been omitted from the figure for clarity. Figure 3 shows that the heat capacity data are rather non-uniformly distributed in (T, m) space and appear to be of limited precision.…”

“…The σ value for V φ includes data to T = 273 K, (18) and excludes Rodyanskii's (16) data at T = 373 K for m ≤ 1.5 mol · kg −1 . The σ for L excludes Ewing and Rogers's (8) data for m ≤ 3 mol · kg −1 . The adjustable parameters β (0) , β (1) , C (0) , C (1) , C (2) , and the infinite dilution quantities C o p,φ {Ca(NO 3 ) 2 } and V o φ {Ca(NO 3 ) 2 } were fit with a function of temperature (T ), pressure ( p), and water density (ρ w ) with the form:…”