Question

Give the relationship between molecular formulae and empirical formulae.

Answer 1

Definition of Molecular Formula:

1. The chemical formula that represents the number of atoms of all the elements in the molecule.

Definition of Empirical Formula:

1. The chemical formula that represents the simplest ratio of the number of atoms of all the elements in the molecule.

Relationship Between Molecular Formula and Empirical Formula:

$\mathrm{Molecular}\mathrm{formula}=\mathrm{n}\times \mathrm{Empirical}\mathrm{formula}$, where $\mathrm{n}$ is any whole number.

Example:

1. The molecular formula of benzene is $\mathbf{\left(}{\mathbf{C}}_{\mathbf{6}}{\mathbf{H}}_{\mathbf{6}}\mathbf{\right)}$.
2. The empirical formula of benzene is $\mathbf{\left(}\mathbf{CH}\mathbf{\right)}$.
3. For benzene $\mathrm{n}=6$.