Chem. 262 Notes

Chem. 262 Notes - 2. 2. Assuming caffeine has a solubility...

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Experiment 1: a solvent-solvent extraction will be used to separate an organic component from a mixture with an acidic compound. A liquid-liquid extraction which relied on differing solubilities of acidic, basic, and neutral compounds was used to separate the mixture. The organic layer must be immiscible with aqueous solutions. The acid is regenerated by treating the aqueous solution with concentrated sulfuric acid 1. Why is your acidic unknown soluble in aqueous base but not in aqueous acid? 1. The acidic unknown was soluble in aqueous base and not aqueous acid because the base deprotonates the acid and allows it to take its conjugate base form` which allows it to stay mixed with the aqueous base. If the acid was extracted with aqueous acid, only the basic salt would be extracted from the solution.
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Unformatted text preview: 2. 2. Assuming caffeine has a solubility of 64 g in 100 mL of dichloromethane and a solubility of 4.0 g in 100 mL of water, a. What is the partition coefficient for the extraction of caffeine in a dichloromethane water solvent system? Show your work. b. How much caffeine is obtained if a solution containing 5.0 g of caffeine in 100 mL of water was extracted once with 100 mL of dichloromethane? Show your work. c. How much caffeine is obtained if a solution containing 5.0 g of caffeine in 100 mL of water was extracted twice with 50 mL of dichloromethane each time? Show your work. 3. A) = Partition Coefficient = Phase 2Phase 1 64 g100 mL 4 g100 = mL 16 g B) = q + = + = . = . V1V1 KV2n 100100 161001 0 05885g 0 294 g C) = q + = + = . = . V1V1 KV2n 5050 161001 0 00355g 0 0046 g...
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This note was uploaded on 05/20/2011 for the course CHEM 262 taught by Professor Forbes during the Spring '08 term at UNC.

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