CHEMISTRY COMMUNITY

What is the difference between enthalpy of formation versus reaction enthalpy?

Standard enthalpy of formation is the enthalpy change of the reaction for which it is formed in reactant/product standard states. Standard reaction enthalpy is the difference between standard enthalpies of formation of the products and reactants. Thus, you use the enthalpies of formation to solve for the reaction enthalpy.

The enthalpy of formation is the change in enthalpy between elements in their standard state and the compound. It is the measure of energy when one mole of product is formed. The standard enthalpy of formation for any element in its standard state is zero. The reaction enthalpy, however, is the difference in enthalpy between reactants and products, and it calculates the heat released or required for any mass, amount of volume of product formed or reactant consumed.

They're related but enthrall of formation describes the energy change that results from the formation of a product.