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How to Do Hot Filtration & Recrystallization in the Chem Lab

Chemical reaction in a laboratory beaker with liquid and solid components.

Find out how everything in a chemistry lab works, from pipettes to burners to recrystallization to storage. You'll get precise instructions on how to work and perform certain scientific duties in the chem lab, whether it's chemical or just ordinary high school science.

Watch this video on how to do hot filtration and recrystallization in the chem lab. The movie explains how hot filtration and recrystallization of 4-methoxy-2-nitroacetanilide yielded certain results.

These are purification methods for crystalline compounds containing a small number of impurities. Insoluble impurities are removed by a filter paper by hot filtration. Soluble impurities in the solution after the filtration are removed by recrystallization. Even if the solubility of impurities is comparable with that of the sample, the impurities are not incorporated in the crystals but left dissolved in the solution when the crystals grow slowly. Do not shake or quickly cool the sample solution. Otherwise, small crystals with low purity form.

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