Pure substances and mixtures
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Electricity
Waves
Forces and motion
Energy
Earth and atmosphere
Acids and alkalis
Chemical reactions
Pure and impure substances
The periodic table and properties of materials
Atoms, elements and compounds
States of matter
Genetics and evolution
Interactions and interdependencies
Plants
Human reproduction
Human gas exchange systems
Human nutrition, digestion and health
Human skeleton and muscles
Explainer Video
Summary
Pure substances and mixtures
In a nutshell
A pure substance consists of one element or one compound. A mixture contains two or more different substances.
Pure substances
A pure substance consists of one element or one compound. Pure substances cannot be separated into anything simpler without undergoing a chemical reaction.
Examples
Water molecules and diamond are examples of pure substances. Pure water contains molecules only. Pure diamond contains the element carbon only.
Mixtures
A mixture contains two or more different substances. It is easy to separate the substances because they are not chemically joined together.
Example
Air is a great example. It consists of a few gases such as nitrogen, oxygen and methane which can all be separated from each other using physical methods.
Tip: Do not confuse mixtures with compounds. Compounds require a chemical reaction to separate them.
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FAQs - Frequently Asked Questions
What is the difference between compounds and mixtures?
Mixtures are substances formed by physically mixing two or more substances together. Compounds are substances formed by a chemical reaction of two or more elements.
What is an example of a mixture?
Air is a great example of a mixture. It consists of a few gases such as nitrogen, oxygen and methane. These gases are all 'mixed' together in the air but it is easy to separate them from each other.
What is a mixture?
A mixture contains two or more different substances.
What is a pure substance?
A pure substance consists of one element or one compound.