What is a balanced equation?

A balanced chemical equation is a chemists shorthand using chemical symbols to show the molecules and atoms of a chemical reaction. The reactants are presented on the left side of the equation and the products are on the right. Coefficients give information regarding the number of molecules involved and the subscripts provide information about the number of atoms in each molecule.

Let us begin with a very basic chemical reaction between nitrogen and hydrogen to create ammonia

The reaction is
Reactants #-># Products
#N_2 + H_2 -> NH_3#
Two atoms nitrogen react with two atoms hydrogen to yield a molecule of ammonia with one nitrogen atom and three hydrogen atoms.

The first step is to take an atom inventory of both sides of the equation.

Reactants
N = 2
H = 2

Products
N = 1
H = 3

To balance the unbalanced atoms of nitrogen we add a coefficient of 2 in front of the ammonia on the product side.

#N_2 + H_2 -> 2NH_3#

This changes the atom inventory of both sides of the equation.

Reactants
N = 2
H = 2

Products
N = 2
H = 6

To complete balancing the equation we add a coefficient of 3 in front of the hydrogen on the reactant side.

#N_2 + 3H_2 -> 2NH_3#

This changes the atom inventory of both sides of the equation.

Reactants
N = 2
H = 6

Products
N = 2
H = 6

And the equation is balanced.
#N_2 + 3H_2 -> 2NH_3#
ONe molecule with two atoms nitrogen react with three molecules with two atoms hydrogen to yield a 2 molecules of ammonia with one nitrogen atom and three hydrogen atoms.

Please review the video below to see more examples of balancing equations.

I hope this was helpful.
SMARTERTEACHER