Sublimation
To demonstrate sublimation.
What students learn
The science behind this experiment
Sublimation is the change of state from solid to gas without passing through the liquid state. This experiment examines how iodine behaves on heating.
Sublimation is a change of state in which matter passes from the solid state directly to vapour.
In the case of some substances such as iodine, naphthalene etc, sublimation occurs quite easily because the solids have quite a high vapour pressure. Their vapour pressure becomes equal to atmospheric pressure before the melting point is reached and so the solid passes straight from solid to vapour without melting.
Equipment used
- Test tubes — 1473.60
- Test tube rack — 1680.06
- Test tube holder — 5423.30
- Spatula — 5460.34
- Spirit burner — 5514.10
Chemicals and reagents
- Iodine — R:20/21-50 S:23-25-61
- Acetone — R:11-36-66-67 S:9-16-26
Safety notes
- This experiment must be performed in a fume cupboard or outdoors.
- Take care when using the burner and hot glassware.
Questions for students
- Record your observations of what happens.
What to expect
<p>On heating the test tube, the iodine crystals produce a purple vapour and crystals of iodine appear on the cooler part of the test tube.</p>
Disposal
Clean the glassware when cool, and the spatula, with propanone (acetone) and dispose of the iodine solution in the flammable wastes container.
Run this experiment in your classroom
This experiment is part of the ATP Mobile Lab — a self-contained laboratory that turns an ordinary classroom into a working science lab, with over 200 experiments in physics, chemistry, biology, robotics and engineering. Gali, the AI tutor built into ATP Connect, guides students through each step and answers their questions at the bench.
See the Mobile LabTalk to our team