Enthalpy provides fast and easy access to formation enthalpy, free enthalpy and entropy of 130+ moleclues. Reaction enthalpies can also be quickly calculated with the results of a calorimetric experiment. We support metric units as well as imperial units. Does oxygen react with copper without any activation energy? Enthalpy delivers reaction enthalpy, free enthalpy and entropy of a reaction within seconds, you only have to choose reactants and products from our growing list of molecules.