crude trimyristin - Chemistry

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PROCEDURE Weigh out 10 g of ground nutmeg and place it in a 500 mL round bottom flask. Add 90 mL of hexane and a few boiling chips and set up an apparatus for reflux (See the figure on page 125) . Reflux the hexane-nutmeg mixture, using a steam bath (see Safety: above) as the source of heat, for 30 min. Determine the mass of your clean, dry 250 mL round bottom flask, containing a few boiling stones. Remove the mixture from the steam bath (dry any water from the flask and condenser before removing the condenser from the flask) and while it is still warm, filter off the residue of the nutmeg by gravity filtration, collecting the filtrate in the preweighed 250 mL round bottom flask. Rinse out the flask in which you did the original extraction (i.e. the 500 mL flask) with about 5-10 mL of fresh hexane and filter the washings into the 250 mL flask. Dispose of the filter paper in the dump in the fume hood. Set up the apparatus for simple distillation (See the figure on page 124) and distil off the hexane using a steam bath. Record the temperature (to the nearest 0.5 °C) when the first drop of distillate is collected in the collection flask and record the highest temperature reached during the distillation. This will be the collection range for the distillation. Continue heating for 5 minutes after the last of the hexane has distilled over. Dry any water from the distillation flask and connecting adapter. Dispose of the distilled hexane in the appropriate dump in the fume hood (make sure you know which flask contains the hexane). Remove the flask containing the crude product and weigh the flask. Record the mass of crude product. At this point, the sample likely contains a trace of hexane and will therefore show an artificially high mass. Leave the flask containing the crude product in your locker for a week (uncorked). After the product has dried for a week, determine the mass of the flask. Record the mass. Did the mass change over the week? Store this round bottom flask in your locker until it is purified in the next lab period. - 4 - REPORT In the “purpose section”, clearly explain the purpose of the main steps in this experiment. In the “discussion section”, comment on the change in product mass from week one to week two. Calculate the percentage recovery of product (be sure to base this on the mass of product after it has dried for a week) and compare this to the expected value (see note 2). List sources of error to account for any discrepancy.
QUESTIONS (FALL 2010) 1. After the reflux, the mixture is filtered to remove the solid residue. This filtration should be done while the solution is still warm. Why? 2. Explain the difference between a saturated solution and a saturated hydrocarbon. Your explanation should explain what the word “saturated” refers to in each case. 3. BRIEFLY - how would you determine how much fat is present in a sample of hamburger? QUESTIONS (WINTER 2011) 1. If there was no water flowing in the condenser during the reflux step, what effect would this have on the results of the experiment? 2. If the nutmeg had been refluxed with water instead of hexane, would the experiment have been successful? Explain. - 5 - 3. When percolating coffee from ground coffee beans, why should the water be near the boiling point (instead of room temperature)?
Page 1 and 2: EXPERIMENT 1 ISOLATION OF OIL OF NU
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crude trimyristin - Chemistry

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