The fact that matter is not created or destroyed in any change in matter is described by the?
That is called the "Law of Conservation of Mass". In general, if something - in this case mass - isn't created or destroyed, in other words, if its total amount remains constant, we talk about a "law of conservation".
Is this an example of chemical reactions Energy is created as atoms are destroyed in chemical reactions?
No Energy can not be created or destroyed, it can only change form Matter cannot be created or destroyed, it can only change form. -- - -- Like stated above, energy can't be destroyed nor created. Only harnessed to only than be used and changed in form. Matter however CAN be destroyed, its exactly what an atomic bomb, hydrogen bomb or nuclear reaction plant does; annihilates molecules harnessing its potential energy. The law of conservation…
You are confusing the law of conservation of matter/mass with the law of conservation of energy. The law of conservation of matter/mass states that in a closed system matter is neither created nor destroyed. During a chemical reaction matter is rearranged, it doesn't change forms (energy can change forms). The atoms in the products are the same atoms that were in the reactants.