Question

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

Answer 1

A  balanced chemical equation is one, in which the total mass of the reactants is equal to the total mass of the products, i.e. the total no. of atoms on the LHS is equal to the total no. of atoms on the RHS. A chem. eq. is balanced in order to make it obey the LAW OF CONSERVATION OF MASS, that states that, the total mass of products=total mass of reactants, i.e. mass is neither created nor destroyed during a chem. reaction.
For example:-
H₂+O₂----->H₂O
This eq. is unbalanced as on LHS, total atoms=2+2=4 and on RHS=2+1=3
Let's balance it:-
2H₂+O₂------>2H₂O
Here, no. of atoms on LHS=RHS=6

Answer 2

A balanced chemical equation is such a reaction written with the representation of different elements in the form of symbols such that:
1.The sum total of atoms of each element in the reactant side should be equal to the sum total of atoms of that element in the product side.
2.The total mass of reactants=Total mass of products.
Eg: $2H_{2} + O_{2} =2 H_{2}O$.

An equation should be balanced so that the law of conservation of mass is obeyed in every reaction.It states that mass can neither be created nor destroyed;it can just be converted from 1 form to another.