Study of the interaction between ionic salts and water and by high-resolution calorimetry

The solubility behaviour of several hydrated and anhydrous sulphates has been studied isothermally (26.2±0.06 °C) by using the high-resolution calorimeter previously described. The notion of behaviour recently defined in terms of topoenergetic principles was adopted for these experiments by establishing standard experimental conditions (SEC), mainly covering the geometry of the measuring cell and the figure of merit of the overall calorimetric system. The previously defined parameters from the heat flow recorded at normal and high speed clearly show the oscillatory behaviour generally predicted by the topoenergetic theory. The measuring system used also allows the demonstration of a difference in behaviour for size fractions of the same solute. The overall solubility behaviour under the same SEC for all values of solute mass can be defined in accordance with the universal topoenergetic procedure applied to a large variety of composite and measuring systems. The resulting data associated with the individual (ontogenic) and the group (phylogenic) behaviour can provide Data Banks for general use.