What is a balanced chemical equation? Why should chemical equations be balanced?

Explanation

A chemical equation having an equal number of atoms of different elements in the reactants and products is called a balanced chemical equation. Here is an example. Zinc reacts with dilute sulphuric acid to form ainc sulphate and hydrogen :
`underset("Zinc")(Zn)+underset("Sulphuric acid")(H_(2)SO_(4))to underset("Zinc sulphate")(ZnSO_(4))+underset("Hydrogen")(H_(2))`
Now this equation has an equal number of `Zn` atoms (1 each) `H` atoms (2 each) S atoms (1 each)and `O` atoms (4 each) in reactants and products so it is a balanced chemical equation.
THe chemical equations are balanced to satisfy the law of conservation of mass which says that matter (or atoms) can neighter be created nor destroyed in a chemical reaction. So the total mass of all the elements present in the products of a chemical reaction should be equal to the total mass of all the elements presents in the reactants. In other words, the number of atoms of each element in the products must be equal to the number of atoms of these elements in the reactants.