Chemical reactions can be represented symbolically using chemical equations. in a chemical equation, reactants appear to the left of the arrow, while products appear to the right. the law of conservation of mass states that matter is neither created nor destroyed in a chemical reaction; rather, the existing atoms are just rearranged. therefore, chemical equations must be balanced—that is, the same number of each kind of atom must be present before and after a chemical reaction.
an unbalanced chemical equation is shown below. balance the equation according to the law of conservation of mass.