Balanced equations have the same number and types of atoms on both sides to the equation as shown for C6H12 below.
Note that atom-counting is an essential part of balancing equations.
To count the total number of atoms of a particular type that are present in a balanced equation
If the atom count shows an unequal number of one or more atoms on both sides of the balanced equation, then one or more of coefficients must be adjusted to make the number and types of atoms equal.
C6H12 + 9O2 
6CO2 + 6H2O
6C 12H 18O 6C (12 + 6 O) 12H
6CO2 + 6H2O6C 12H 18O
6C (12 + 6 O) 12HNote that atom-counting is an essential part of balancing equations.
To count the total number of atoms of a particular type that are present in a balanced equation
multiply the subscript on that atom in the formula for the substance by the coefficient on the formula
The total O in the reactants above is 9 (the coefficient on O2) × 2 (the subscript on O2)
add the results if the atom appears in more than one substance on the same side of the equation.
In the products there are 12 O for CO2 (6 × 2) plus 6 O for H2O (6 × 1)
The total O in the reactants above is 9 (the coefficient on O2) × 2 (the subscript on O2)
add the results if the atom appears in more than one substance on the same side of the equation.
In the products there are 12 O for CO2 (6 × 2) plus 6 O for H2O (6 × 1)
If the atom count shows an unequal number of one or more atoms on both sides of the balanced equation, then one or more of coefficients must be adjusted to make the number and types of atoms equal.
Never adjust the subscripts in the formulae because these represent the actual composition of the compound.