Conservation of Energy and Matter: Introduction
In the previous section you learned about chemical reactions and about exothermic and endothermic processes. Think about how atoms in the reactants change into the products as a chemical reaction proceeds. It is important to understand that atoms are neither created nor destroyed as chemical reactions take place. Atoms are only rearranged. It is also important to realize that regardless of whether a reaction is exothermic or endothermic, no new energy is created or destroyed; it must come from somewhere, and it must go somewhere.
Neither matter nor energy ever disappears, though both can change form and move through space. In this section, you will learn about two basic laws of physical science: the law of conservation of energy and the law of conservation of matter. You will see how each applies to chemical reactions and learn that as chemical reactions proceed, matter and energy must always be accounted for.
