Molcular and Empirical Formula

Molecular Formula

A molecular formula shows the actual number of atoms of different elements in a molecule of a compound. For example, a molecule of water consists of two hydrogen atoms and one oxygen atom. So its molecular formula is written as H₂O.

Empirical Formula

Empirical formula of a compound gives only relative number of atoms of different elements. These numbers are expressed as the simplest ratio. For example, empirical formula of glucose, which consists of carbon, hydrogen and oxygen in the ratio of 1:2:1 is CH₂O.

Molecular formula of a substance is always an integral multiple of its empirical formula.

Molecular Formula = X_n (X is empirical formula)