A chemical equation is a written symbolic representation of a chemical reaction .The substances undergoing reaction are called reactants, and their formulas areplaced on the left side of the equation. The substances generated by the reaction are called products, and their formulas are placed on the right sight of the equation.Plus signs (+) separate individual reactant and product formulas, and an arrow(⟶) separates the reactant and product (left and right) sides of the equation.