Definition
The heat is given off during a reaction.
Explanation
During a reaction, the heat or energy that is released during the process, is due to the change of enthalpy of a chemical reaction.
Heat of Reaction
In one sentence
During a reaction, the heat or energy that is released during the process, is due to the change of enthalpy of a chemical reaction.
Terms used on this page
Every one of these links to a full definition with an example.