C1, P1 Fractional Distillation

What is fractional distillation used for?

Separating a mixture of liquids with different boiling points.

Describe the method of fractional distillation.

1. Gently heat the mixture in a flask. 2. Both liquids evaporate, but the liquid with the lower boiling point evaporates more easily. 3. Vapours enter the fractionating column, where repeated condensation and evaporation help the lower-boiling liquid rise. 4. Vapour passes into the condenser and cools into a liquid. 5. Collect the first liquid when the thermometer reaches a constant temperature at its boiling point. Repeat for the higher-boiling liquid.

What is the function of the fractionating column?

It allows repeated evaporation and condensation, helping separate liquids with different boiling points.

What does a constant thermometer reading mean?

A liquid is boiling and mainly that liquid's vapour is passing into the condenser, allowing it to be collected as a fraction.

What makes fractional distillation difficult?

Liquids with very similar boiling points are harder to separate and may require several rounds of distillation