Distillation

D. Crowley, 2007

Distillation

To know when to use distillation, and to be able to explain how it works

Wednesday, April 19, 2023Wednesday, April 19, 2023

Lost At Sea

Imagine you were really stuck for water whilst at sea

Sea water is so salty that it dehydrates you quicker than not drinking any water at all (as well as sending you mad)!

If you were stranded on the boat, and it wasn’t likely to rain, how could you change the salt water into drinkable water in order to survive?

Evaporation

Evaporation would separate the two (the salt and water), but it would only leave as the salt

The water would be lost as it evaporates away, but this is a good start…

Distillation

Distillation can separate a liquid from a solution (water from salty water)

Distillation works by evaporating the liquid from the solution

It is then cooled and condensed into a separate container

The salt does not evaporate, so we have successfully separated the two…

Distillation

Demo of distillation

Boiling Temperature

It is really important you know the boiling temperature of the liquid you want

The liquid will only be removed once it reaches this boiling point (at which point it can be condensed and collected)

This means different substances can be separated, based on their boiling temperature - this is the science behind distillation

Boiling Temperature

E.g. water and ethanol have different boiling points - the ethanol will boil first (78oC), and then the water (100oC) enabling us to separate the two

This is known as fractional distillation

Worksheet

Complete the distillation worksheet…