The statement, "Energy can neither be created nor destroyed, but can change from one form to another," is what law?

In chemical reaction, atoms always are rearranged. They are never destroyed or created because it would contradict the law of conservation of energy. The law of conservation of energy states that energy can neither be created nor destroyed, but can change from one form to another. Also it cannot be neutralized. Resulting in one cannot be part of a chemical reaction. An example of this is the reaction HCl + NaOH - > NaCl + H2O. the reactants and products are not created, they are just formed into another substance.