crystallization_steps

crystallization_steps - Summary of The Recrystallization...

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Summary of The Recrystallization Steps: 1. Choose The Solvent : "Like dissolves like." Examine your compound and determine its polarity before you choose a solvent for recrystallization. For common solvents, consider Table 1 on the next page. These solvents decrease in polarity down the list. 2. Dissolve The Solute : To crushed or ground solute in a small test tube—for rice size amounts—or in a Erlenmeyer flask—for large amounts—add hot solvent and keep the solution hot on a hot plate. Add enough solvent to dissolve most of the crystals. If crystallization begins fairly rapidly after removing from the heat, add more hot solvent. 3. Decolorizing The Solvent : If there are colored impurities, cool the solution somewhat and carefully add charcoal. If you are using charcoal pellets, add some, then swirl to see if all the color disappears. If your are using powder, add a small portion (about 10% of the amount of sample) and stir. Heat gently for a few minutes. Gravity filter the charcoal from the solution, keeping the solution as hot as possible.
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This note was uploaded on 09/09/2011 for the course CHEM 231l taught by Professor Gergens during the Spring '11 term at Mesa CC.

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