Question

You are handed a mixture of sand and salt. How do you separate the two substances? Anything added to the mixture has to be retrieved. [6 marks]

Answer 1

1. A mixture of sand and salt is taken in a beaker and water is added to it. [1 mark]
2. After a few seconds of stirring, since salt is soluble in water, the salt will dissolve into the water. [1 mark]
3. The sand being heavier settles at the bottom of the beaker by a process which is known as sedimentation. [1 mark]
4. The sand can be separated from the salt solution by decantation or filtration. [1 mark]
5. The remaining mixture of salt and water is heated and the water evaporates to form water vapour. [1 mark]
6. Now, only salt is left in the beaker and the water vapour can be converted back into water through condensation. [1 mark]