Lab session 4

Crystallization

As promised, today we did an experiment on crystallization. In this practical, we formed Copper (II) Sulfate crystals. 

 Materials needed:
- Copper (II) Sulphate (powder form)
-Distilled water
- Spatula
- Filter funnel
- Filter paper
- Boiling tube
- Evaporating dish
- Beaker
- Bunsen Burner
- Tripod stand + wire gauze
- Glass rod
- Peg / tongs

Step 1: Pour 20ml of distilled water into the beaker. Setting it on the wire gauze on the tripod stand, heat the water to a boil. Stop heating when the water starts to boil.

Step 2: Pour 1 spatula of Copper (II) Sulphate into the hot water. Stir with the glass rod until all of the powder has dissolved.

Repeat step 2 until the Copper (II) Sulfate cannot be dissolved.
Step 4: Filter the solution into the evaporating dish. Use the glass rod to help.

Step 5: Heat the solution in the evaporating dish over the bunsen burner. Stop heating when half of the solvent has evaporated from the solution. DO NOT HEAT TO DRYNESS. (If a crust forms on the surface, add distilled water to dissolve the crust. Stir with glass rod.)

Step 6: Using a pair of tongs, carefully grip the evaporating dish and pour its contents into the boiling tube. Since we're doing slow cooling, leave the boiling tube to cool.

(You can see the crystals starting to form already. :D)

(My friend accidentally spilt a bit on the table and it crystallized immediately. XD)

Now, we'll leave it for a week or so to wait for the crystals to develop. Stay tuned! :)

After a two week wait, here are the crystals formed:

Some Demos: 

IODINE SUBLIMATION: Separating iodine from sand

(Heating of mixture of solid iodine balls and sand)

(As can be seen, the dark purple gas is the iodine gas. Sublimation is the transformation from solid directly to gas.)

Separation funnel

Separating oil from colored water

The separation funnel is used to separate liquids of different densities. Since water is denser than oil, water is collected first, then oil. The separating funnel is controlled by a tap.