Science Ace 2!!!

This was my second Ace project!!


Name: Tan Jin Neng, Clarence
Class: 1A3 (28)
Term 3 Science Ace
Experiment on obtaining water from salt water
Introduction:
Mixtures are not chemically joined and we can use physical methods to obtain the components of the mixture. The various separation techniques are Filtering, Chromatography, Distillation, Fractional Distillation and Evaporation.
A solution is a mixture. It is formed when a solid, a liquid or a gas dissolves in a liquid. For example, if you stir salt into water, the salt dissolves. It breaks up into individual salt molecules. The solution is now a mixture of water molecules and salt molecules. The salt is called the solute and the water is called the solvent.
Experiment set up:
As we have learnt that we can obtain a solvent from a solution using distillation, I shall do an experiment on distillation to obtain water from salt solution, not in the laboratory but at home. Since it is at home, I do not have the necessary laboratory apparatus like flask, Bunsen burner, condenser, etc, I shall make use of some kitchen utensils.
These are the things that I am going to use for the experiment: A cup of water, some salt (sodium chloride), an empty saucer, cooking pot, aluminum foil, ice cubes and a spoon.
First, I shall dissolve some salt into the water. Stir it until the salt dissolves.
Next I pour the salt solution into the cooking pot.
Place the pot onto a stove. Place the empty saucer in the cooking pot. Cover the pot with an aluminum foil and put some ice cubes on the foil.
Heat the salt solution until all the ice cubes have melted.
Remove the aluminum foil and take out the saucer from the cooking pot.
Some water is collected in the saucer. We can further test if the water is pure by boiling it. If it boils at 100°C, it means the water is pure.

Conclusion:
The melting and boiling points of salt and water are tabulated below:
Salt Water
Boiling point 1413°C 100°C
Melting point 801°C 0°C

As water has a lower boiling point than salt, 100°C (water) compared to 1413°C (salt), water evaporates first when the salt solution is heated. Water vapour condenses to form water droplets when in contact with a cool surface which is the aluminum foil with ice cubes on it. As the weight of the ice cubes form a depression on the centre of the aluminum foil, the water droplets then drip into the saucer. The salt will not evaporate yet as its boiling point is 1413°C and therefore is left in the pot.



These are the link to my videos as i cannot upload them ):
http://www.youtube.com/watch?v=xPICTyqui40
http://www.youtube.com/watch?v=eeipv9xCdtM
http://www.youtube.com/watch?v=HtfOQLt4QRs