A chemical reaction is a process in which one or more substances, the reactants, are converted to one or more different substances, the products.
Substances can be elements or compounds.
A chemical reaction is represented by a chemical equation, as follows:
REACTANTS → PRODUCTS
It reads: REACTANTS YIELD PRODUCTS
During a chemical reaction the atoms present in the reactants (also called reagents) break some bonds and form new ones to create different substances called products.
No elements are destroyed or created, so the atoms on the left of the equation (reactants) must match the elements on the right of the equation (products).
This “matching” on the left and the right of the equation is attained by balancing the chemical reaction.