Recrystallisation revision cards on each step of recrystallisation 3.0 / 5 based on 2 ratings ? ChemistryReactionsA2/A-level Created by: aCreated on: 24-01-11 19:03 Choosing a solvent Choose a solvent that the impure substance is NOT soluble in a LOW temperatures but is COMPLETELY soluble in at HIGHER temperatures. Add as small amount as possible. 1 of 4 Heating Once the solvent has been added to the impure substance, heat the mixture until the impure solid has completely dissolved A water bath or bunsen burner could be used for this 2 of 4 Cooling Cool the solution until crystals have formed You could cool it in an ice bath If crystals don't form then too much solvent may have been used. So allow some of the solvent to evaporate and then heat the solution again and re-cool. 3 of 4 Vacuum filtration Wash the crystals with cold solvent Pour the solution/crystals into the Buchner funnel and turn on the vacuum pump. The part you want to keep is the solid that hasn't passed through the funnel. Dry the solid, this can be just left in the air to dry 4 of 4
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