Question

Why must a chemical equation be balanced?

Short answer

A chemical equation must be balanced to follow the law of conservation of mass which states that matter cannot be created nor destroyed. In chemical reactions, the total mass of the reactants equals the total mass of the products which is depicted in a balanced chemical equation.

Step-by-step solution

Understanding a chemical equation

A chemical equation is a symbolic representation of a chemical reaction. It consists of reactants (substances getting consumed in the reaction) on the left, products (substances produced in the reaction) on the right and an arrow which shows the direction of the reaction. The substances are represented by their respective chemical formulae.

The Importance of Balancing a Chemical Equation

According to the law of conservation of mass, matter cannot be created nor destroyed. This implies that the total mass of the reactants must equal the total mass of the products. In a chemical equation, this is shown by making sure there are the same number of each type of atom on both sides of the equation. If the equation is not balanced, it implies that atoms are either being created or destroyed which violates the fundamental principles of physics.

Example of a Balanced Chemical Equation

Let's look at a simple example, the formation of water from hydrogen and oxygen: \[2 H_2 + O_2 \rightarrow 2 H_2O\]. In this chemical equation, we have 4 hydrogen atoms and 2 oxygen atoms on both sides of the equation, therefore it is balanced.