Question

How can a chemical equation be balanced?

Answer 1

According to the law of conservation of mass, when a chemical reaction occurs, the mass of the products should be equal to the mass of the reactants. Therefore, the amount of the atoms in each element does not change in the chemical reaction. As a result, the chemical equation that shows the chemical reaction needs to be balanced. A balanced chemical equation occurs when the number of atoms involved in the reactants side is equal to the number of atoms in the products side.
Example:
$N_2+H_2\to N{H}_3$ Not balanced equation.

To balance the chemical equation above, we need to make use of coefficients. A coefficient is a number that we place in front of a chemical formula.

$N_2+3H_2\to 2N{H}_3$

The equation above is now balanced. There are 2 nitrogen (N) atoms and 6 hydrogen (H) atoms on both the reactants and products side. Since there is no coefficient in front of N${}_2$, that means the coefficient is equal to 1.