1. Always have the same composition and are formed by chemical processes.
Pure Substances
Always have the same composition and
are formed by chemical processes.
Either elements or compounds.
Examples:
Pure water (H2O), carbon dioxide (CO2), hydrogen (H2), gold (Au)
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2. Have variable composition. Examples Wood, wine, coffee, granite
Mixtures
Have variable composition.
Examples
Wood, wine, coffee, granite
Can be separated into pure substances: elements and/or compounds using physical processes.

3. Having visibly indistinguishable parts. A solution.
Homogeneous Mixture
Same throughout.
Having visibly indistinguishable parts.
A solution.
Does not vary in composition from one region to another.
Apple Juice Salt and water Orange Juice

4. Heterogeneous Mixture
Having visibly distinguishable parts.
Contains regions that have different properties from those of other regions.

5. How can mixtures be separated?
If you have a salad containing an ingredient you don't like, how can you remove it?
This ppt introduces and reviews ways of separating mixtures

6. Physical properties-Separation techniques
Melting point
Boiling point
Freezing point
Density
Electrical conductivity
Magnetic
Particle size

7. a) Magnet b) Filtration c) Chromatography d) Distillation
Separation techniques
How can we physically separate (purify) substances from mixtures and solutions into pure substances?
a) Magnet b) Filtration c) Chromatography d) Distillation
Physical means are those that do not change the nature of the substances being separated.

8. A magnet
Can be used to separate a magnetic substance from a non-magnetic substance
(Magnetic properties)
Magnets are used in the re-cycling industry to separate ferrous and non ferrous metals.

9. Filtration
Funnel
Filtration can be used to separate an insoluble substance from a soluble substance
(heterogenous mixture)
Ex. Coffee grounds are separated by water through filtration
Solid
Here you can introduce the terms Filtrate and residue.
Liquid

10. Chromatography
From Greek Chroma which means "color" and graphein "to write"
Used to separate complex mixtures that rely on the differential affinities of substances
Ex. Paper chromatography separate black ink into the colored dyes it contains.

11. Separate substances that have different boiling points
Distillation
Separate substances that have different boiling points
Ex. Separating alcohol from water
Boiling pt of alcohol is 70 C.
Boiling pt of water is 100 C.
The liquid is boiled to produce a vapor that is then condensed into a liquid.

12. Separating a Heterogeneous Mixture
Sample Problem
Separating a Heterogeneous Mixture
How could a mixture of aluminum nails and iron nails be separated?
Analyze Identify the relevant concepts. 1
In order to identify how to separate aluminum and iron nails, the properties of both aluminum and iron must be known.
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13. Solve Apply concepts to this situation.
Sample Problem
Solve Apply concepts to this situation. 2
List the properties of each substance in the mixture.
Iron
metal
gray color
doesn’t dissolve in water
attracted to magnet
Aluminum
metal
gray color
doesn’t dissolve in water
not attracted to magnet
You could use a magnet to remove the iron nails from a mixture of iron and aluminum.

14. Distillation relies on the boiling point of the substance.
Which physical property does filtration rely on to separate mixtures? Which does distillation rely on?
Filtration relies on the size of a particle, or molecule, of a substance.
Distillation relies on the boiling point of the substance.

15. Classification of Matter