Chemical Engineering - Chemical Reaction Engineering - Discussion

The Heat of Reaction is the change in the enthalpy of a chemical reaction that occurs at a constant pressure. It is a thermodynamic unit of measurement useful for calculating the amount of energy per mole either released or produced in a reaction.

Since enthalpy is derived from pressure, volume, and internal energy, all of which are state functions, enthalpy is also a state function.

So, the heat of reaction is dependent on the physical states of reactants and products, allotropic forms of elements, temperature, and reaction carried out at constant pressure or constant volume.