What this topic covers
Topic 8: Chemical analysis has 3 subtopics:
- Purity, formulations and chromatography
- Identification of common gases
- Identification of ions by chemical and spectroscopic means (chemistry only)
← Back to topics
GCSE AQA Higher Combined Science Chemistry · Topic 8 of 11
Topic 8: Chemical analysis – GCSE AQA Higher Combined Science Chemistry revision notes
Choose a subtopic. Topic 8: Chemical analysis covers Purity, formulations and chromatography, Identification of common gases, and Identification of ions by chemical and spectroscopic means (chemistry only) in GCSE AQA Higher Combined Science Chemistry. 9 lessons in 3 subtopics.
Revise Topic 8: Chemical analysis for GCSE AQA Higher Combined Science Chemistry, including Purity, formulations and chromatography.
9
Lessons
3
Subtopics
Topic 8: Chemical analysis lessons by subtopic
9 lessons, grouped by subtopic.
Purity, formulations and chromatography
- Paper Chromatography - Principles and Applications
- Chromatogram Analysis and Rf Values
- Understanding Formulations
- What is a Pure Substance?
- Using Melting and Boiling Points to Test Purity
Identification of common gases
Revise Right Mocks '26
AQA GCSE Combined Science Chemistry mock draft, 26–31 Oct. Draft coverage: Combined Science Chemistry Paper 1 (Higher tier). Reviewed for an original-practice sitting; check student availability before registering. Marking and results will follow later, after separate approval. Eligible new accounts receive a five-day Pro trial when signup email verification completes. Previous trials keep their original expiry. After expiry, new papers need Pro unless you have an explicitly confirmed free sitting offer for this event. That offer adds no Pro time or AI learning. Saved attempts and released results remain readable. No card or automatic charge.
More in this course
Go back to the full GCSE AQA Higher Combined Science Chemistry topic list, or practise this topic with past-paper questions.
Frequently asked questions
What is Topic 8: Chemical analysis?
Topic 8: Chemical analysis covers Purity, formulations and chromatography, Identification of common gases, and Identification of ions by chemical and spectroscopic means (chemistry only) in GCSE AQA Higher Combined Science Chemistry. 9 lessons in 3 subtopics.
What is a chromatogram?
A chromatogram is the pattern of separated substances produced by chromatography, showing spots at different distances from the origin. The Chromatogram Analysis and Rf Values notes cover this in full.
What is the test for hydrogen?
The test for hydrogen is to hold a burning splint at the mouth of the test tube: if hydrogen is present, it burns rapidly with a pop sound. The Testing for hydrogen gas notes cover this in full.
How do you calculate an Rf value?
Rf = distance moved by substance ÷ distance moved by solvent, both measured from the origin. The Chromatogram Analysis and Rf Values notes cover this in full.
What is the test for oxygen?
The test for oxygen is to put a glowing splint into a test tube of the gas: if oxygen is present, the splint relights. The Testing for Oxygen Gas notes cover this in full.
What is the test for carbon dioxide?
The test for carbon dioxide is to bubble the gas through limewater, or shake it with limewater: carbon dioxide turns limewater milky (cloudy). The Testing for Carbon Dioxide Gas notes cover this in full.
What is a formulation?
A formulation is a mixture that has been designed as a useful product, where each component has a specific purpose and is present in carefully measured quantities. The Understanding Formulations notes cover this in full.
What is the melting point of aspirin?
Pure aspirin melts at 135°C. The Using Melting and Boiling Points to Test Purity notes cover this in full.
What is the test for chlorine?
The test for chlorine is to hold damp litmus paper near the gas: chlorine bleaches the paper and turns it white. The Testing for Chlorine Gas notes cover this in full.