This lesson covers AQA Trilogy Combined Science specification 5.8.1 and introduces key methods used to assess purity and separate mixtures.

Students will:

• Explain the difference between pure substances, mixtures, and formulations, using correct chemical definitions and examples.
• Use melting point, boiling point, and chromatographic evidence to distinguish between pure and impure substances.
• Interpret chromatography results, calculate Rf values, and use them to identify substances or assess purity.

The lesson includes retrieval quizzes, structured activities, and exam-style questions, making it suitable for KS4 classroom teaching or revision.