MM of water is 18. Most small compounds are gasses at room temperature and pressure. H 2 O, bent molecule, two lone pairs. These terminals are also called electrodes. During the process of electrolysis, energy is provided.
Bond energy is like the strength of the bond and has to do with the atoms involved.
For the specific case of water, the electrolysis of water requires 572 kJ of energy per 2 moles of water. We can see that energy is a product of reaction of hydrogen and oxygen and that water is also produced. Look again closely at the exothermic reaction just above. Like the combustion of fuels which produce energy to drive things like automobiles, the combustion of hydrogen also produces energy. The molecule is made out of two O-H bonds.