What are the chemical equations?

A chemical equation is the symbolic representation of a chemical reaction in the form of symbols and formulae, wherein the reactant entities are given on the left-hand side and the product entities on the right-hand side. 

For example, hydrogen gas (H₂) can react (burn) with oxygen gas (O₂) to form water (H20). The chemical equation for this reaction is written as E.g. - H2 + O2 ⇒ H2O.

The '+' is read as 'reacts with' and the arrow '' means 'produces'. The chemical formulas on the left represent the starting substances, called reactants.