The Standard Enthalpy of Hydration (also sometimes know simply as the Enthalpy of Hydration) is defined as “the heat evolved when one mole of gaseous ions become surrounded by water molecules (also known as “hydrated”) when measured under standard conditions.

Enthalpy of hydration also suggests that the higher the ion charges are (and the smaller the actual ions are in relation to the charges), then the greater the chance of the hydration enthalpy being exothermic or outwardly warmer/hotter. Another way of phrasing the definition of “enthalpy of hydration” is “the actual amount of energy that is ‘set free’ when a mole of the ion forming an infinite dilute process – meaning the expended in the hydration processed of an ion.”

It is quite interesting to note that the Enthalpy of Hydration is only applicable if the solvent used to surround the ions happens to be water. If the solvent is not, in fact, water, then the term “Enthalpy of Solvation” is used to replace “Enthalpy of Hydration”.

In this section of the site, we will be providing you with all the information that you need in order to fully grasp not only the concept of enthalpy hydration but also the equation and values that are necessary for calculating it.