Enthalpy

Enthalpy equals heat.

Enthalpy can be represented in the relationship H= E + PV, the enthalpy change, delta H, for a reaction that happens at constant pressure is the heat that is evolved or absorbed in the reaction, delta H =qp.

The enthalpy of formation for heat is the change that is in relation to the formation of a substance from the most stable form of its component elements.

The enthalpy of reaction is the change associated with a chemical reaction.