Crystallization Practical

Question 1

Describe a method for crystallisation.

Answer 1

1) Add powdered insoluble reactant to acid in a beaker, one spatula at a time, stirring to mix. Continue adding powder untill it is in excess.

2) Filter the mixture in the beaker to remove the excess powder. Collect the filtrate.

3) Pour the filtrate into an evaporating basin. Place on a water bath, and heat until about half the water from the solution has been removed by evaporation. Stop heating when small crystals start to appear around the edge of the evaporating basin.

4) Pour the remaining solution into a watch glass, and leave in a warm, dry place for crystallisation to occur.

5) If necessary, dry the crystals by dabbing gently with filter paper.