A pure substance is a substance made from only one element or one compound. And nothing else.
Let’s have a look at some particle diagrams and see if you can work out whether or not they are pure substances.
The box above shows a particle diagram of a gas. Does the diagram above show a pure substance or not? What did you answer? If you said it shows a pure substance, you would be correct! It is a gas made up of just one element. A pure substance.
How about this one below? Pure or not?
Did you say pure? Correct! It is made up of only one type of compound, so it is a pure substance.
Let’s have a go at a few more questions now and attempt to recognise pure substances from particle diagrams.
