Simple distillation enables a liquid to be separated from a solution. First, the solution is heated until the solution with the lowest boiling point evaporates. Then, the vapor is cooled and condenses (turns back into a liquid). Finally, this liquid can be collected, leaving the remaining solution in the flask.

What would happen if the mixture was heated to a temperature higher than the boiling points of both substances?

  • Both liquids will evaporate and then mix again.

Why can distillation separate a mixture of water and ethanol?

  • Ethanol and water have very different boiling points.
  • The solution with the lowest boiling point will reach its boiling point first and start to evaporate.
  • It can then be condensed and collected, separating the mixture.

What is fractional distillation?

Fractional distillation can separate a mixture of liquids with close boiling points.

The liquid with the lowest boiling point will evaporate first. As its boiling point is reached, it changes from a liquid state to a gaseous state.

Why is the fractionating column filled with glass rods?

  • The glass rods provide a larger surface area for condensation and evaporation.

When will children learn about distillation?

Children will learn about distillation during Chemistry lessons in KS3 and KS4. An example of an exam-style question a child may encounter on distillation is;

The answer they would need to give has been written in blue.

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