Calcium Nitrate. Iii. Heats of Hydration and of Solution of the Binary System Calcium Nitrate-Water

Abstract

Ill 1335 with sodium acetate, whose hydrogen-ion concentration is 3.2 X 10 "8 in a tenth molar solution, it would assume a position much nearer the strong nitric acid than the weak acetic acid. Such an approximation would place it near sulfuric acid but below it. Summary 1. The presence of disodium dihydrogen pyrophosphate is given as an explanation for the acidity of solutions of "Graham's salt" and solutions of other sodium metaphosphates prepared by heating monosodium orthophosphate when they are not purified by repeated crystallizations from water.2. The monometaphosphoric acid is near but below sulfuric acid with respect to its activity.

The Apparent Volumes and Apparent Compressibilities of Solutes in Solution. III. Unsaturated and Supersaturated Solutions of Calcium Nitrate

“…From the data given in table 1, values of (apparent molal volume), B (apparent molal compressibility), and f culated by methods already described (10, 11) and are listed in table 2. The relationships between the two apparent properties, and (B +/), of calcium nitrate and the square root of the concentration of this electrolyte are portrayed in figure 1. The solid dots in this graph represent the values given in table 2 and the open circles represent -c* values at 18°C., which were calculated from data tabulated in the International Critical Tables. It should be noted perhaps that the quantities used in constructing the {B + /)-c!…”

“…In one case, stock solution No. 20 was analyzed by the conventional oxalate method as well as by the dehydration method described above, giving the following values for the per cent of calcium nitrate: In a second series of experiments, a solution was prepared by melting crystals of the tetrahydrate -which had been dried in a vacuum desiccator over 60 per cent sulfuric acid (2). Analysis of this stock solution (No.…”