Chemical Thermodynamics and Some Kinetics 1.
Potential energy is the energy possessed by virtue of position or composition.
In an exothermic reaction the value of H of the species is increasing in going from reactants to products. Energy is neither created or destroyed in ordinary chemical reactions. The D H of a reaction tells one the heat liberated or absorbed under constant pressure reaction conditions. The internal energy change of a system equals the heat absorbed minus the work done by the system. The second law states that D S of a system increases in any spontaneous process.