Lipid Written Signature Assignment v5

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University Of Arizona *

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151L

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Chemistry

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Feb 20, 2024

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Chemical Thinking Lipid Written Signature Assignment v5.8| 1 CHEM 151 LWSA v5.8 6-3-23 Lipid Written Signature Assignment Your name: Your email: Your lab partner’s name (s): Your lab partner’s email (s): Your lab instructor’s name: Your lab section: 1. Overall Project Goal (1 pt) . In complete, well-written sentence(s), summarize in your own words the overall goal(s) for the Lipid Project . The overall goals of the lipid project are to explore the solubility of major food components and then use the results to isolate a practice snack food, as well as to learn how to use the iodine test to ensure that the isolated fat is free from starch. Then, write a plan to separate the fat of an unknown snack food while running a control to calculate a isolation control factor. Re-run the iodine test and with the results calculate a fat percentage weight for the unknown snack food. Then write a new plan to run 2 concurrent runs of the same values at the same time with a single control and include how you would calculate the average percent fat weight of the 2 runs. Finally, carry out the plan, determine a new isolation correction factor, calculate the percentage fat weight of both runs, and calculate an average percentage fat weight for both. 2. Implementing Group Proposal 2: Raw Data, Observations and Results (5 pts). Complete Table 8 , which gathers the supporting raw data for your two (2) replicate assigned snack food runs and the concurrent oil control run. Then finish Table 9 . Table 8. Assigned Snack Food (QF6) Replicate Lipid Quantitation Raw Data Assigned Snack Food (Unknown) Mass (finely ground) Volume of Cyclohexane Volume of NaCl Beaker “ 1 ” Mass (m beaker 1 ) Unknown Isolate + Beaker “1” Mass (m 1 ) 0.75 g 2.5ml 2.5 ml 77.238 g 77.988 g 0.75 g 2.5ml 2.5 ml 71.333 g 72.083 g Vegetable Oil (Control) Mass Volume of Cyclohexane Volume of NaCl Beaker 2 Mass (m beaker 2 ) Control Isolate + Beaker 2 Mass (m 2 ) 0.251 g 2.5 ml 2.5 ml 108.338 g 108.589 g Table 9. Assigned Snack Food (QF6) Replicate Lipid Quantitation Results and Observations Assigned Snack Food (Unknown) Unknown Isolate Mass (m ULI ) Observations 0.317 g This value is significantly smaller than the second run 0.390 g This value is significantly bigger than the first run All work must be very neat and organized . If you need to collect your thoughts, please use a separate sheet of paper. Written Signature Assignments are an individual effort for sections 4 - 8 of the present document (while sections 1 - 3 are a group effort). Please individually submit your completed document to the lab Lipid Written Signature Assignment D2L DropBox folder before the scheduled end of lab. Always check to confirm the correct document/file has imported to the correct lab D2L Dropbox folder – no excuses. Submission to an incorrect Dropbox folder will be subject to a 1-point penalty. If you submit an unintended document, or need to update a submission, you can always resubmit so long as you are not past the deadline . If you submit the wrong document and fail to realize this until after the deadline, a resubmission cannot be accepted. So please be careful and always double check!

Chemical Thinking Lipid Written Signature Assignment v5.8| 2 CHEM 151 LWSA v5.8 6-3-23 Vegetable Oil (Control) Control Isolate Mass (m CLI ) Observations 0.174 g This is a smaller value than we got during the second session meaning the experiment was most likely run better last session

Chemical Thinking Lipid Written Signature Assignment v5.8| 3 CHEM 151 LWSA v5.8 6-3-23 3. Implementing Group Proposal 2: Starch Test Results (3 pts) . In the space below, clearly report in complete well-written sentences the iodine-potassium iodide (I 2 -KI) test observations and results for the isolated lipids (of Table 8 ) and the positive and negative test controls concurrently run . The first run of the two concurrent unknown snack runs had a negative test for starch when we put a drop of iodine in the lipid. The drop of iodine turned a reddish orange with no black meaning that there was no starch in the lipid. The second run had the same result, but the drop of iodide stayed more orange than it did in the first run, but because no starch was present the drop of iodine did not turn black. Parts 4 - 8 (the sections below) are strictly an independent (individual) effort. Sorry, no group work! 4. Assigned Snack Food Isolation Correction Factor (3 pts) . Present in a well-organized manner and in complete detail the isolation correction factor for your assigned snack food based only on Tables 8 and 9 . Clearly state symbolically the equation(s) being used, then substitute in actual values, and finally give the results . Mass oil control (original) = 0.251 g Control lipid Isolate Mass = 0.174 g Fc = Mass oil control (original) / Control Lipid Isolate Mass Fc = 0.25 g / 0.174 g = 1.4368 5. Replicate Runs: Assigned Snack Food Percent Fat by Weight (4 pts) . Show the percent fat by weight calculations for your assigned snack food replicate (repeat) runs in a highly organized manner and in complete detail based only on the values from Tables 8 and 9 . Clearly state symbolically, at least once, the equation(s) being used, then present separate calculations for each replicate run . Mass of lipid = Fc * Unknown lipid Isolate mass Mass of lipid (run 1) = 1.4368 * 0.317 g = 0.455 g Mass of lipid (run 2) = 1.4368 * 0.390 g = 0.560 g Percentage fat by weight = Mass of lipid/ Mass of Snack food * 100% Percentage fat by weight (run 1) = 0.455 g / 0.75 g * 100% = 60.667 % Percentage fat by weight (run 2) = 0.560 g / 0.75 g * 100% = 74.667%

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