1Element, compound or mixture?
Element: one kind of atom. Compound: different atoms joined, every particle the same. Mixture: different substances, not joined.
elementcompoundmixture
Lesson 5.3 notes
Elements, compounds and mixtures
Air, sea water and juice are mixtures. Learn to tell elements, compounds and mixtures apart.
2Air is a mixture
Air is mostly nitrogen and oxygen molecules, with a little argon and carbon dioxide. They are mixed, not joined.
air
3A mixture keeps its properties
In a mixture of iron and sulfur, the iron is still magnetic. A magnet pulls it out and leaves the sulfur.
separate
4A compound has new properties
Heat iron and sulfur and they react to make iron sulfide. It's a new substance, and a magnet can't pull the iron out.
react
5Any proportions
A mixture can be weak or strong: the amounts can change. A compound always has a fixed ratio.
proportion
6Separating a mixture
Mixtures can be separated by physical methods. Evaporating salt water leaves the salt behind.
evaporatefiltermagnet
Explore: Sort the diagrams
Is each box an element, a compound or a mixture? Choose, then check.
Common mistake: Two kinds of atom doesn't always mean a compound
If different atoms are joined in every particle, it's a compound. If different particles move about separately, it's a mixture.
Remember
- Element: one kind of atom. Compound: elements joined. Mixture: substances not joined.
- A mixture keeps the properties of its substances, can have any proportions and can be separated by physical methods.
- Air, sea water and fruit juice are mixtures.
Going further at GCSE
GCSE: Mixtures and separation → GCSE: Atoms, elements and compounds →