A sample of a compound of Cl and O reacts with an excess of H2 to give 0.233g of HCl and 0.403g of H2O. Determine the empirical formula of the compound

Cl2O7

Explanation:

Molar mass of HCl = 36.5gmol-1

Molar mass of water = 18gmol-1

To get the ratio of chlorine present in the original substance

0.233/36.5 = 0.00638

To get ratio of oxygen present in the original compound

0.403/18 = 0.0224

Then divide through by the lowest ratio

Cl - 0.00638/0.00638 O - 0.0224/0.00638

Cl - 1 O - 3.5

Multiplying through by 2 to give whole numbers

Cl-2. O-7

Hence the empirical formula of the compound is Cl2O7