1. Separating Substances
Chapter 19.

3. Mixtures A mixture is two substances mingled
Together but not chemically combined.

4. Separate mixtures by
Filtering (to separate soil and water)
Decanting (separate sand and water)
Evaporating (salt and water)
Distilling (alcohol and water)
Chromatography (separate different dyes)

5. Filtration.
Filtration is the method of separating insoluble solid from a liquid using material that allows liquid to pass through but not the solid.
Filtrate is the clear liquid that passes through
Residue is the substance left behind on the filter paper.

11. Decanting (separate sand and water)

13. Evaporation.
Evaporation is used to separate a soluble solid from a liquid when the liquid is not required.
Example: Salt and water.

14. Evaporation can be used to retrieve a solute from a solution.

16. Evaporation

19. Distillation
Distillation is the process involving the vapourisation of a liquid by boiling it and then condensing the vapour by cooling it.
It is based on the fact that the two liquids have different boiling points.

20. Two miscible liquids are liquids which mix together, e. g
Two miscible liquids are liquids which mix together, e.g. alcohol and water.
Alcohol Boiling point 78’c
Water boiling point 100’c

22. Distillation

23. To obtain a sample of water from sea-water using simple distillation
Procedure:
Set up as shown above.
Part C is called a condenser; it has an outer tube which carries cold water which causes the water vapour passing through the inner tube to condense back into a liquid.
Cold water goes in through D and out through B.
The round-bottom flask above the Bunsen burner contains sea-water.

24. Result:
The water evaporates from the round-bottom flask, travels through the condenser where it condenses and flows into the beaker as pure water.

25. Distillation
Showing liebeg condenser

26. Chromatography
Paper chromatography is a technique to separate mixtures of substances in solution.
The solvent in which the substances are dissolved is passed along a length of paper and the dissolved substances separate out on the paper.

27. Chromatography
p.64 Experiment Book

28. Learning check