ENTHALPY CHANGE DURING THE FORMATION OF SOLUTIONS AND CRYSTALLOHYDRATES IN LIOH – H2O, NAOH – H2O AND KOH – H2O SYSTEMS AT 298.15 K

On the basis of reference data, enthalpy changes were calculated during the formation of solutions and crystallohydrates in the LiOH – H2O, NaOH – H2O and KOH – H2O systems when the corresponding hydroxides were mixed with water at a temperature of 298.15 K. When creating graphical dependences of entropy changes during the formation of solutions and crystallohydrates in MeON – H2O systems, it was meant that in the two–phase regions of MeON – H2O systems, the enthalpy changes linearly depend on the composition. Module changes in enthalpy during the formation of solutions and crystallohydrates increase at the point of LiOH – H2O system transition to the KOH – H2O system. The results of the calculations indicate that, using the literature data on the integral heats of dissolution and enthalpy of formation of crystallohydrates in systems, it is possible to obtain information about changes in enthalpy during the interaction of hydroxides with water with the formation of solutions and crystallohydrates.