LEFT CLICK OR PRESS SPACE BAR TO ADVANCE, PRESS P BUTTON TO GO BACK, PRESS ESC BUTTON TO END LEFT CLICK OR PRESS SPACE BAR TO ADVANCE, PRESS P BUTTON TO GO BACK, PRESS ESC BUTTON TO END COMPUTER PRESENTATIONS FOR KS3 SCIENCE - CHEMISTRY ©2003, STEVE PARKER COMPUTER PRESENTATIONS FOR KS3 SCIENCE - CHEMISTRY ©2003, STEVE PARKER

1 1 KS3 SCIENCE - CHEMISTRY KS3 SCIENCE - CHEMISTRY Separation Techniques Separation Techniques

2 2 FILTRATION

3 3 The constituent parts of a Mixture are not joined Chemically, so they can be separated quite easily The constituent parts of a Mixture are not joined Chemically, so they can be separated quite easily In Filtration, a mixture is passed through something which only allows one part through In Filtration, a mixture is passed through something which only allows one part through

4 4 FILTRATION We can do this using Filter Paper inside a Filter Funnel, which allows liquid through and holds back any solids We can do this using Filter Paper inside a Filter Funnel, which allows liquid through and holds back any solids

5 5 FILTRATION FILTER PAPER RESIDUE FILTRATE

6 6 EVAPORATION

7 7 Solutions of a Solute in a Solvent can be separated by Evaporation Solutions of a Solute in a Solvent can be separated by Evaporation

8 8 EVAPORATION If you Boil off half the liquid and leave the dish in a warm place, the solvent Evaporates, leaving Crystals of the solute behind If you Boil off half the liquid and leave the dish in a warm place, the solvent Evaporates, leaving Crystals of the solute behind

9 9 EVAPORATION But be careful! But be careful!

10 EVAPORATION Rocksalt is a mixture of sand and salt, and we can extract salt from the mixture by first using water to Dissolve the salt Rocksalt is a mixture of sand and salt, and we can extract salt from the mixture by first using water to Dissolve the salt This leaves us with a salt solution and some sand This leaves us with a salt solution and some sand

11 EVAPORATION We can now filter the sand out from the salt solution We can now filter the sand out from the salt solution

12 EVAPORATION And finally evaporate the water to get the salt crystals And finally evaporate the water to get the salt crystals

13 CHROMATOGRAPHY

14 CHROMATOGRAPHY First put a spot of ink on some filter paper and cut a strip to fold down as a wick, before dipping the wick in solvent First put a spot of ink on some filter paper and cut a strip to fold down as a wick, before dipping the wick in solvent

15 CHROMATOGRAPHY The solvent moves through the filter paper and the ink, but different dyes in the ink will wash out at different rates The solvent moves through the filter paper and the ink, but different dyes in the ink will wash out at different rates

16 DISTILLATION

17 DISTILLATION To Distil a liquid from a solution, we boil it and then condense the resulting gas by passing cold water around it To Distil a liquid from a solution, we boil it and then condense the resulting gas by passing cold water around it WATER

18 DISTILLATION WATER The gas then turns back into a liquid and is collected below, while the solute is left behind in the flask The gas then turns back into a liquid and is collected below, while the solute is left behind in the flask

19 DISTILLATION Fractional Distillation is used for separating a mixture that contains several different liquids Fractional Distillation is used for separating a mixture that contains several different liquids Different liquids have different boiling points, so the temperature is gradually raised to boil off one liquid at a time Different liquids have different boiling points, so the temperature is gradually raised to boil off one liquid at a time

20 DISTILLATION This is how crude oil from the ground is Refined to produce fuel for planes and petrol for cars This is how crude oil from the ground is Refined to produce fuel for planes and petrol for cars