Answer
An empirical formula is the simplest positive integer ratio, and the molecular formula represents the real amount of atoms together in a molecule of this compound.
If the real amount of atoms in a molecule are already the simplest positive integer ratio, which means that they cannot be divided to get lower integers, the empirical formula is equal to the molecular formula.
Work Step by Step
For example:
We find the empirical formula to be $C_2H_5O$ in an experiment.
That means that the molecular formula of that same compound is $C_{2n}H_{5n}O_{n}$.
Where "n" can be any integer; if it happens to be equal to 1, the empirical formula is equal to the molecular formula.
