Separation Techniques

This lesson covers the key separation techniques you need to know for the Edexcel GCSE Combined Science specification (1SC0): filtration, evaporation and crystallisation, simple distillation, fractional distillation and chromatography. You need to understand when to use each method, how it works, and the scientific principles behind it.

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Choosing the Right Technique

The method used to separate a mixture depends on the physical properties of the components.

graph TD
    A["What type of<br/>mixture is it?"] --> B{"Insoluble solid<br/>in a liquid?"}
    B -->|Yes| C["Filtration"]
    B -->|No| D{"Dissolved solid<br/>in a solution?"}
    D -->|"Want the solid"| E["Evaporation /<br/>Crystallisation"]
    D -->|"Want the solvent"| F["Simple Distillation"]
    D -->|No| G{"Two or more liquids<br/>with different BPs?"}
    G -->|Yes| H["Fractional<br/>Distillation"]
    G -->|No| I{"Dissolved substances<br/>to identify?"}
    I -->|Yes| J["Chromatography"]

    style A fill:#2c3e50,color:#fff
    style B fill:#2980b9,color:#fff
    style C fill:#27ae60,color:#fff
    style D fill:#2980b9,color:#fff
    style E fill:#27ae60,color:#fff
    style F fill:#27ae60,color:#fff
    style G fill:#2980b9,color:#fff
    style H fill:#27ae60,color:#fff
    style I fill:#2980b9,color:#fff
    style J fill:#27ae60,color:#fff

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1. Filtration

Filtration separates an insoluble solid from a liquid.

Method