Loading please wait

The smart way to improve grades

Comprehensive & curriculum aligned

Try an activity or get started for free

Understand Some Differences Between Pure and Impure Substances

In this worksheet, students will learn about some of the differences between pure and impure substances.

'Understand Some Differences Between Pure and Impure Substances ' worksheet

Key stage:  KS 3

Year:  Year 8 Science worksheets

Curriculum topic:   Chemistry: Pure and Impure Substances

Curriculum subtopic:   Concept of a Pure Substance

Difficulty level:  

Worksheet Overview

Have you heard the word 'pure' before?


In chemistry, we refer to a pure substance as being a substance made from only one element or one compound. And nothing else.


The opposite of a pure substance is an impure substance. An impure substance is one made from more than one element or one compound, meaning it is a mixture.


A substance being impure doesn't mean it's necessarily bad. Water taken straight from a mountain stream would be classed as impure as it would contain more than just water molecules - it would also probably contain some impurities such as salt, dissolved gases and microorganisms. 


mountain scene


A pure substance has a fixed melting point and boiling point, which means they will always melt or boil at exactly the same temperature. For example, pure water has a melting point of 0°C and its boiling point is 100°C.


If you added some impurities to this water, say in the form of some salt or sugar, it would change the melting and boiling point, showing us that the water is now impure.




Got it? Let's try some questions.

What is EdPlace?

We're your National Curriculum aligned online education content provider helping each child succeed in English, maths and science from year 1 to GCSE. With an EdPlace account you’ll be able to track and measure progress, helping each child achieve their best. We build confidence and attainment by personalising each child’s learning at a level that suits them.

Get started

Try an activity or get started for free

  • National Tutoring Awards 2023 Shortlisted / Parents
    National Tutoring Awards 2023 Shortlisted
  • Private-Tutoring-WINNER-EducationInvestor-Awards / Parents
    Winner - Private Tutoring
  • Bett Awards Finalist / Parents
  • Winner - Best for Home Learning / Parents
    Winner - Best for Home Learning / Parents