The empirical formula is the simplest formula of any compound.It expresses the simplest ratio of all the atoms or ions that makeup a certain compound. For example, the empirical formula ofthe compound with the formula, C2H4is CH2. This means thatthe simplest ratio of (C:H) is 1:2. This ratio also indicates theratio in which carbon and hydrogen atoms combine to form thecompound C2H4.
The molecular formula is the formula which shows the actual number of all atoms present in a given compound. For example,the molecular formula of the above compound is C2H4. This means that two atoms of carbon and four atoms of hydrogen form the compound. Likewise, the molecular formula of water isH2O meaning that the compound is made up of two atoms of hydrogen and one atom of oxygen.