Write the empirical formula corresponding to each of the following molecular formulas: (e) C6H4Cl2

Key Concepts

Empirical Formula

The empirical formula of a compound represents the simplest whole-number ratio of the elements present in that compound. It does not provide information about the actual number of atoms in a molecule but rather the relative proportions of each element. For example, the empirical formula for glucose (C6H12O6) is CH2O, indicating a 1:2:1 ratio of carbon, hydrogen, and oxygen.

Molecular Formula

The molecular formula of a compound indicates the actual number of each type of atom in a molecule. It provides more specific information than the empirical formula, as it reflects the true composition of the substance. For instance, the molecular formula C6H4Cl2 shows that there are six carbon atoms, four hydrogen atoms, and two chlorine atoms in each molecule of the compound.

Reduction of Ratios

To derive the empirical formula from a molecular formula, one must reduce the ratios of the elements to their simplest form. This involves dividing the number of atoms of each element by their greatest common divisor. In the case of C6H4Cl2, the ratio of carbon to hydrogen to chlorine is already in its simplest form, leading to the empirical formula C3H2Cl.