Explain what is water of crystallization

Explanation:

In chemistry, water(s) of crystallization or water(s) of hydration are water molecules that are present inside [crystal]s. Water is often incorporated in the formation of crystals from aqueous solutions. ... Water of crystallization can generally be removed by heating a sample but the crystalline properties are often lost

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.