The molecular formula of a compound is related to its empirical formula as follows:

Molecular formula = n × Empirical formula

Where, n may be 1, 2, 3 …

The value of n can be obtained by the following relationship.


n = molecular mass / Empirical formula mass

For example, the empirical formula of a compound having molecular mass of 78 up is CH. So,

n = Molecular mass / Empirical formula = 78u / (12+1) u= 78u/ 13u=6

Therefore, the molecular formula of the given compound is 6 × (CH) = C6H6