After a reaction, chemists rarely end up with just the compound they wanted — there's almost always something else in the mix. This video surveys all the main separation techniques you need to know for GCSE: filtration, evaporation, crystallisation, distillation, fractional distillation, and chromatography. It explains the principle behind each one and connects them to real-world examples so you know when to choose which technique.

What You Will Learn

00:56What a heterogeneous mixture is and why particle size is the key property that determines how to separate it.

02:37What a homogeneous mixture is and why solutions require different separation techniques from suspensions.

04:33What an alloy is and why it is classified as a solid-state mixture rather than a compound.

05:17What a solution, solute, and solvent are and what aqueous means in a chemical context.

07:16How filtration separates an insoluble solid from a liquid.

07:57How evaporation and crystallisation recover a dissolved solid from a solution.

08:24How distillation separates a liquid from a solution by exploiting differences in boiling point.

08:44How fractional distillation separates a mixture of liquids with different boiling points.

08:49How chromatography separates dissolved substances based on their different interactions with the stationary and mobile phases.

10:01How crude oil is separated into fractions and why gas separation by liquefaction is used for air.