How to carry out a single-solvent recrystallization

Examples Suppose that you have prepared a crude sample (about 4.0 g) of A/-phenylethanamide (acetanilide) and you are to purify if by recrystallization -from water. The melting point of pure A/-phenylethanamide is 114 C (tide, 2000). 

Weigh the crude sample and retain a few crystals in case seeding is required. 

Transfer the solid, using glazed paper or a solids funnel (p. 25), into a clean, dry conical flask (250 mL). 

Add cold water (about 100 mL) and a glass rod as an anti-bumping device to the flask and then heat the mixture on a hot plate until the compound has dissolved completely. Then add more water (about 10 mL), to ensure that precipitation of the solute does not occur during the following stages. 

Remove the flask from the heat and allow it to cool for 2 minutes. 

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