Compounds & Mixtures
Science: KS3, topic 2.3.3
Compounds and Mixtures
A compound or mixture is made when there are two or more different atoms in a material.
Compounds
- A compound is when the different atoms are joined or linked together. It is difficult to separate the different atoms because they are glued together in a ‘chemical bond’.
- Examples of compounds include:
- Carbon dioxide (carbon and oxygen elements joined).
- Water (hydrogen and oxygen elements joined).
- Plastic (carbon, oxygen, hydrogen and usually other atoms too depending on the type of plastic).
Mixtures
- A mixture is when the different atoms are not joined together.
- So the different atoms can be separated.
- Imagine a bag of skittles:
- All the different flavours can be separated into piles because they are just mixed in the bag, not joined together.
Mixtures (cont.)
- A mixture can be made of two or more different compounds as well.
- As long as there are two different parts then a mixture can be a mixture of: elements and other elements, compounds and other compounds, or elements and compounds.
- The air we breathe is a mixture of oxygen, carbon dioxide, argon and other gases.
Test yourself on Compounds & Mixtures
Which is an example of a compound?
Which of these is a mixture?
Which of these are true of mixtures and compounds?
Which of these terms describes air?
Why are the gases in air easier to separate than the atoms in carbon dioxide?