Classify the following as molecules of elements or compounds. Water, methane, ozone, phosphorus, nitrogen, slaked lime, salt, vinegar, calcium carbonate.

Molecules of elements - Ozone (${\text{O}}_3$), Phosphorus (${\text{P}}_4$)and Nitrogen (${\text{N}}_2$) [1 Mark]
Molecules of compounds - Water (${\text{H}}_2\text{O}$), Methane (${\text{CH}}_4$), Slaked lime (${\text{Ca(OH)}}_2$), salt ($\text{N}aCl$), Vinegar (${\text{CH}}_3\text{COOH}$), Calcium carbonate (${\text{CaCO}}_3$). [1 Mark]