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Unformatted text preview: IN LAB:- weighed out 100 mg caffeine, added 1.5mL H2O, add 1.5mL dichloromethane- transfer bottom layer to Erlenmeyer- weigh Erlenmeyer=24.436g- add NaSO4 let dry 10 minutes- use filter pipet to move organic liquid to new flask- add 1mL dichloromethane to make sure all caffeine is obtained- filter again- add boiling stones- boiled off organic liquid- weight=24.516g placed caffeine in heavy walled test tube filled flared test tube with 16 water and place it in heavy walled and heated to sublime scraped off caffeine from inner tube = wt= 0.057g put sample in capillary tube, flame sealed one end took melting point 226-228C post lab::::::::::::::::/results and calculations 1. mass recovery crude caffeine 24.516g-24.436g=0.08g=80mg crude caffeine % recover crude caffeine is the mass recovered/inital mass x100= [80/100]x100=80% recovery 2. mass recovered for pure caffeine = 0.057g =57mg pure caffeine % recovered pure caffeine = [57/100]x100= 57% pure caffeine CHART----------------- product | initial mass | recovered mass | % recovered MP (C)...
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This note was uploaded on 08/14/2010 for the course BIO 2010 taught by Professor Le during the Summer '10 term at UCSB.
- Summer '10