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Unformatted text preview: Recrystallization Parts III / IV Lab Report (01-April- 2007) Norbert Wang GSI: N. Stephanopoulos 105 Purpose: The purpose of this lab is to learn how to recrystallize a pure substance out of a solution and to remove colored impurities with activated charcoal. This laboratory procedure involved recrystallization of an unknown substance. This process requires saturating the solute(s) in a solvent at a high temperature and then cooling the solution slowly down to room or ice temperature allowing pure solute(s) to recrystallize out of the original mixture. These crystals were then washed with cold solvent and filtered out of the solution and dried. Firstly, a test was necessary to determine a good solvent to perform the recrystallization. Compound H needed to be very insoluble in the solvent at around 0-25 C and very soluble in the solvent at a higher temperature. Each of the members of the group tested a small amount of sample with six potential solvents: ethanol, acetone, ethyl acetate, toluene, hexane, and water. Each trial involved attempting to dissolve the unknown into the solvent first at room temperature and then at a higher temperature using sand bath. Ethanol turned out to be the best solvent because compound H remained insoluble in ethanol at room temperature and completely soluble in ethanol at around 105 C (17, B). The remaining sample of compound H was evenly divided among group members. Each member The remaining sample of compound H was evenly divided among group members....
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This note was uploaded on 09/21/2009 for the course CHEM Chemistry taught by Professor Nitche during the Spring '08 term at Berkeley.
- Spring '08