GlossariesGCSE GlossariesGCSE Chemistry GlossaryPure Substance

Pure Substance - GCSE Chemistry Definition

Reviewed by: Richard Boole

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A pure substance is a material that contains only one type of element or compound, with a uniform composition throughout. It has no other substances mixed in.

For example:

  • Pure water (H2O) contains only water molecules.

  • Pure oxygen (O2) contains only oxygen molecules.

Pure substances have sharp boiling and melting points, which help identify them. This is different from mixtures, which may melt or boil over a range of temperatures.

In GCSE Chemistry, understanding pure substances is important for studying chemical reactions, purity testing, and separating mixtures.

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Richard Boole

Reviewer: Richard Boole

Expertise: Chemistry Content Creator

Richard has taught Chemistry for over 15 years as well as working as a science tutor, examiner, content creator and author. He wasn’t the greatest at exams and only discovered how to revise in his final year at university. That knowledge made him want to help students learn how to revise, challenge them to think about what they actually know and hopefully succeed; so here he is, happily, at SME.

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