Recrystallization is the a technique used to purifying solid compounds. Recrystallization is the process of a crystalline solute is dissolved in a (hot) solvent and then returned to its state when cooled in a solvent by crystallizing.Crystals formation is a process.
During recrystallization the solute is dissolved in a hot solvent destroying impurities. Once it has been heated, it is then cooled in a cold solvent selectively producing purer crystals.
Recrystallization is a purifying method used in chemistry to purify solutes.Recrystallization depends greatly on polarity as the solvents used for recrystallization must have a similar polarity to the solvent used to dissolved it. The cold solvent must have the opposite polarity of the solvent to get crystals as a product. After being purified one can use percent yield to determine how much of the chemical was purified and the identity of the solute.
Procedure
Weigh 0.5g of salicylic acid and dissolved it with 5ml of alcohol
Observation
The salicylic acid dissolved in the 5ml of the alcohol upon shaking to form a clear solution at room temperature with no visible reaction.
Procedure
Weigh 0.5g of salicylic acid and dissolved it with 5ml of water
Observation
The salicylic acid was insoluble in 5ml of water upon shaking at room temperature with no visible reaction. Some of the salicylic acid suspended upon shaking for some time and later settled down.
Further heating the salicylic acid +water, the salicylic acid dissolved to form a clear solution
Procedure
Weigh 0.5g of benzoic acid and dissolved it with 5ml of alcohol
Observation
The benzoic acid dissolved in the 5ml of the alcohol upon shaking to form a clear solution at room temperature with no visible reaction.
Procedure
Weigh 0.5g of benzoic acid and dissolved it with 5ml of water
Observation
The benzoic acid was insoluble in 5ml of water upon shaking at room temperature with no visible reaction. Some of the benzoic acid suspended upon shaking for some time and later settled down.
Further heating the benzoic acid +water, the benzoic acid dissolved to form a clear solution
In the example, if you started with 5.00 grams of your chemical before the recrystallization procedure, you would calculate 2.86 divided by 5.00 to obtain 0.572. Multiply the result of your last calculation by 100. The result is your percent recovery of that chemical for the procedure.
What is an acceptable percent recovery? The recovery for accepted range in analytical chemistry is 70-120%.
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