Due to the vast amounts of chemical reactions happening around us, a nomenclature was developed to simplify how we express a chemical reaction in the form of a chemical equation. A chemical equation is nothing but a mathematical statement which symbolizes the product formation from reactants while stating certain condition for which how the reaction has been conducted.
The reactants are on the left-hand side whereas products formed on the right-hand side connected by a one-headed or two-headed arrows. For example, a reaction
A + B → C + D
Here, A and B are the reactants, which react to form the products C and D. In an actual chemical equation, reactants are denoted by their chemical formula. In order to assure the law of conservation of mass, a chemical equation must be balanced i.e. the number of atoms on both sides must be equal. This is the balancing of the equation.
Let us consider an actual chemical reaction between Methane(CH₄) and Oxygen (O2),
Here we can see how the number of each atom on the left side is balanced on the right side, as stated by the law of conservation of mass.