The enthalpy of dissolution is the change in the thermodynamic potential of a substance when it is dissolved at a constant pressure in a solvent until it reaches an infinite dilution. The enthalpy of dissolution is commonly expressed at a common temperature in kJ/mol.
Enthalpies of dissolution can result in exothermic and endothermic reactions. The three steps involved with dissolution determine the thermodynamic properties of the reaction. First, the solute-to-solute attractions are broken down, resulting in an endothermic value. Second, the solvent-to-solvent attractions are broken down resulting in an endothermic value. Finally, the solvent-to-solute attractions are broken down, resulting in an exothermic value. The aggregate of these values determines if the overall reaction was endothermic or exothermic.