State four differences between elements and compounds.

A mixture of sand and ammonium chloride can be separated by

1. filtration
2. distillation
3. sublimation
4. crystallization

This gas is highly soluble in water

1. Ammonia
2. Nitrogen
3. Oxygen
4. Carbon monoxide

Which of the following methods is used to separate potassium nitrate and sodium chloride from their mixture ?

1. distillation
2. crystallisation
3. fractional distillation
4. fractional crystallisation