Enthalpies for Different Types of Reactions

Enthalpy of Formation :
It is the heat change when one mole of compound is obtained from its constituent elements. Enthalpy of formation at standard state is known as standard enthalpy of formation and is taken as zero by convention.

Enthalpy of Combustion :
It is the enthalpy change taking place when one mole of a compound undergoes complete combustion in the  presence of oxygen. It is always negative, because process of combustion is exothermic.

Enthalpy of Solution :
It is the enthalpy change when one mole of a substance is dissolved in large excess of solvent, so that on further dilution no appreciable heat change occur.

Enthalpy of Hydration :
It is the enthalpy change when one mole of anhydrous substance undergoes complete combustion. It is an exothermic process.

Enthalpy of Fusion :
It is the enthalpy change that accompanies melting of one mole of solid substance.

Enthalpy of Vaporisation :
It is the enthalpy change that accompanies conversion of one mole of liquid substance completely into vapours.

Enthalpy of Neutralisation :
It is the enthalpy change that takes place when 1 g-equivalent of an acid (or base) is neutralised by 1 g-equivalent of an base (or acid) in dilute solution.

Enthalpy of Transition :
It is the enthalpy change when one mole of the substance undergoes transition from one allotropic form to another.

Enthalpy of Atomisation :
It is the enthalpy change occurring when one mole of the molecule breaks into its atoms.

Enthalpy of Dilution :
It is the enthalpy change when one mole of a substance is diluted from one concentration to another.

Enthalpy of Sublimation :
It is the enthalpy change when one mole of a solid substance sublimes.

Lattice Enthalpy :
It is the enthalpy change when one mole of an ionic compound dissociates into its ions in gaseous state.

Bond Enthalpy :
Enthalpy is required to break a bond and energy is released when bond is formed.