Describe two reasons for balancing chemical equations.
Chemical equations are balanced in order to: 1) satisfy the Law of Conservation of Mass, and 2) establish the mole relationships needed for stoichiometric calculations.
The Law of Conservation of Mass:
The Law of Conservation of Mass states that mass cannot be created or destroyed. Therefore, mass is not gained or lost in a chemical reaction. This means that the total mass of the reactants in a chemical reaction is equal to the total mass of the products. In order for the mass of the reactants to be equal to the mass of the products, there must be the same number of each type of atom on the reactant and product sides of the equation. Balancing chemical equations ensures that the same numbers of each type of atom are present on both sides of the equation.
Stoichiometric calculations are used to predict the amount of substance in one part of a chemical equation based on the amount of substance in another part of the chemical equation. The relationship between the two substances is described by their mole ratio. The mole ratio between two substances is the same as the ratio of their coefficients. Balancing chemical equations ensures the correct ratio of moles between the substances in a chemical reaction.