the is the distallition expirment of an orginic chem class i want the pre and po
ID: 1001091 • Letter: T
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the is the distallition expirment of an orginic chem class i want the pre and post lab questions to be solved as soon as possible.
Measure 30 mL of an unknown mixture into a 100-mL round-bottom flask and add 2-3 boiling stones. You should then set up your distillation apparatus as shown in figures 1 (simple) or 2 (fractional) and follow the basic experimental outline discussed in the introduction. Leave enough space between the graduated cylinder and take-off adaptor so that you can easily switch between the graduated cylinder and a vial. Ensure that water is flowing through the condenser and all of your joints are secure. Have your TA check your distillation setup before heating. Also, have three one-dram vials on hand to collect samples of your distillate. You are now ready to begin the distillation. Plug in the voltage controller and slowly commence heating. Heating too rapidly can ruin your distillation and result in misidentification of the unknown mixture. Remember to aim for~10 drops per minute. In your notebook, keep a log of the volume of distillate collected and the corresponding temperature. You should have an entry for at le st every 1 mL. You should collect small samples in labeled vials at the following intervals: 6 mL, 15 mL, and 22 mL. Once you have collected the final sample, you should stop the distillation. You only need fill the vial 1/3 full. These vials must be tightly capped to prevent evaporation. Be sure to record in your notebook exactly when you collect each sample. Temperature plateaus during the distillation process correspond to the boiling point of each component in the mixture. If you have three plateaus, your unknown corresponds to the three-component mixture (Unknown 1). If you have only two temperature plateaus, then your unknown is either mixture 2, 3, or 4. By comparing the distillation temperatures observed with the boiling points of the esters, you can determine the identity of your unknown mixture. Unknown 2: Each vial should contain one of the three esters as its major component. Unknowns 2-4: Vial 2 can be discarded. Vial 1 should contain the lower boiling point ester while vial 3 should contain the higher boiling point ester. a) Toluene b) Acetonitrile c) Anthracene 6. Consider each pair of compounds listed below and determine whether a fractional distillation would be necessary to separate them. Look up the boiling points at www.sigmaaldrich.com. a) Ethyl acetate and hexane b) Diethyl Ether and 1 -butanol c) Bromobenzene and 1, 2-dibromobenzene D. Post-Lab Questions 1. Plot a graph that has the volume of distillate of the x-axis and distillation temperature on the y-axis. You can do this using graph paper or on a spreadsheet program. a) Indicate the ranges where each component is distilling over. b) Based on your curve, how many components are present in your unknown mixture? c) What is the boiling range for each component? d) Indicate on your graph the points where you collected vial samples. e) What is the identity of the major component in each vial? f) Based on your data, what compounds are present in your unknown? 1. Compare and contrast the observed differences between the simple distillation and the fractional distillationExplanation / Answer
Pre-Lab.
Question 1: Boiling pearls can identify when a liquid boiling process began, the function in the distillation is precisely indicate the time starts and ends the distillate of the fractions in question.
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