Which statement describes a chemical reaction?
atoms in the products are rearranged to form new substances.
atoms in the reactants are rearranged to form new substances.
atoms in the products change into new atoms to form new substances.
atoms in the reactants change into new atoms to form new substances.

The correct answer is: Atoms in the reactants are rearranged to form new substances. A chemical reaction has two parts: The reactants and the products. Reactants are used to make products. Atoms are the smallest form of matter and can not be further broken down. They do not change into new atoms but can be rearranged. Thus, in the correct answer, atoms in the reactants, what is listed before a chemical reaction arrow), are simply rearranged in different combinations to form new substances or new products.