2. Pure substance Only one kind of material
Definite properties that are the same throughout
Types
a) elements
b) compounds

3. Elements cannot be changed into simpler substances by chemical change
Smallest particle is the atom

4. Compounds
pure substances made up of one or more elements chemically combined
Can be broken down into simpler substances by heat, electricity or other means
Properties may be different than the elements which make up the compound

5. Mixture Each substance keeps its own specific properties
Not the same throughout
Not chemically combined
Can be separated by physical means (filtration or distillation)

6. Heterogeneous Mixture
Least mixed
Large particles
Suspension
Examples: concrete, oil & vinegar

7. Homogeneous Mixtures Appears the same throughout
Particles do not settle when mixture allowed to stand
Types
a) solution
b) colloid

8. Solution One substance dissolves in another
Solute: substance that dissolves
Solvent: substance that does the dissolving
Not easily physically separated by filtering
Particles too small to scatter light
Looks clear and transparent
Every part tastes the same

9. Colloid Particles are mixed together but not dissolved – e.g. milk
Particles are permanently suspended
Will NOT separate on standing
Usually looks cloudy – scatters light
Medium sized particles

10. Types of mixtures