Enthalpies of solution in water and (methanol + water) at 298.15 K and enthalpies of transfer

Abstract

Enthalpies of solution of the anhydrous alkali-metal chlorides and of barium chloride and strontium chloride were determined calorimetrically in water and aqueous methanol at 298.15 K. The enthalpies of transfer from water to (methanol + water) were obtained by difference. The present results are compared with those reported in the literature, and discussed. At around 10 to 20 mass per cent of methanol, a maximum is clearly observed in the enthalpy of solution; this is discussed in terms of hydrogen bonding and structural changes of (water + methanol). The experimental enthalpies of transfer are larger than those calculated on the basis of Born's equation. This is expected because the theoretical calculations do not take into consideration the effects of structural changes; hence a simple comparison is not justified.