The enthalpy change that occurs when one mole of a compound is formed from its constituent elements in their standard states.
Heat of Reaction: The total amount of heat absorbed or released during a chemical reaction.
The amount of energy required to break one mole of a bond in a substance to separate atoms in gas phase.
A law stating that the total enthalpy change for a reaction is independent of the pathway, i.e., it depends only on the initial and final states.