Activity 5.7 To seperate camphor from sand by sublimation. Class 9

Activity 5.7 To seperate camphor from sand by sublimation. Class 9

Activity 5.7

Aim: To seperate camphor from sand by sublimation.

Procedure:

1. Take a spatula and place it on the tripod stand using a wire gauze.
2. Take a clean and dry glass funnel. Plug its nozzle with cotton.
3. Keep this funnel inverted on the china dish and set up the apparatus as shown in Fig.
4. Light the burner and place it under the wire gauze.
5. Heat the china dish gently for a few minutes.
6. Observe the inner wall of the funnel carefully. Do you notice any solid deposits?
7. You may find white, solid camphor deposits on the inner wall of the funnel while sand remains in the china dish.

Observation:

On gentle heating, the mixture of camphor changes directly from solid to vapour.

The camphor does not melt - instead, it directly converts from solid to vapour without passing through the liquid state. While, solid camphor deposits appear on the inner wall of the inverted glass funnel, as the vapours cool down and solidify on the cooler surface of the funnel. The sand remains behind in the china dish, as it does not undergo sublimation. The cotton plug in the nozzle of the funnel prevents the camphor vapours from escaping.

Conclusion:

Sublimation is used to separate a sublimable substance (camphor) from a non-sublimable substance (sand).