Study Hub

Study Guides

This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.

Back to Study HubBrowse Year 7 Science Guides

Year 7 - Science

Pure substances

Solutions

Unit Summary

This unit explores the concepts of pure substances, mixtures, and diffusion in liquids and gases. It emphasises accuracy, precision, and the use of appropriate techniques during investigations. The focus is on making predictions and recording reliable observations.

Lesson Summary

You will learn to describe the difference between a pure substance and a mixture.

Key Notes

  • A pure material is made of only one type of substance
  • A pure material has a fixed melting point and boiling point
  • Impurities change the melting and boiling point of a material
  • A mixture contains two or more types of substances which can be easily separated
  • Mixtures melt or boil over a range of temperatures

Vocabulary To Learn

  • pure substance: A pure substance contains only one type of chemical
  • mixture: A mixture is a material that contains two or more different substances which can be physically separated
  • impurity: An impurity is a chemical that is found in a material in very small amounts, but can change the material's properties

Common Mistakes To Avoid

  • Pupils mistake common (everyday) usage of pure (i.e. 'pure orange juice) as being a pure substance

3 Quick Questions (With Answers)

1. Explain the scientific idea in this lesson using two key points.

A pure material is made of only one type of substance. A pure material has a fixed melting point and boiling point.

2. Define this scientific word and use it in context. 'pure substance'

A pure substance contains only one type of chemical. Include the word in a full scientific explanation, not as a single label.

3. Correct this common scientific misunderstanding.

Mistake: Pupils mistake common (everyday) usage of pure (i.e. 'pure orange juice) as being a pure substance. Correction: 'Everyday' usage refers to one *source* whereas scientific usage refers to particle composition. Take particular care when discussing water.

More Lessons In This Unit

Browse all guides in the Year 7 Science guide library.