Chem+102+Quiz+5+2010b+-+answers

Chem+102+Quiz+5+2010b+-+answers - mol 0253 S.A. mol 1...

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Quiz #5 Name Lab Section: Show all your work and provide all calculated answers with the correct number of sig. fig. 1. In your own words, state Le Chatelier’s Principle. (2 pt) Le Chatelier’s Principle states that when a chemical system at equilibrium is stressed (by a change in concentration, temperature, …), the equilibrium composition of reactants/products will change so that the effect of the stress will be minimized. 2. How many millimoles are in a 1.75 g sample of aspirin (180.2 g/mole) has? (2 pt) Aspirin mmol 71 9 mol 1 mmol 1000 Aspirin mol 00971 0 Aspirin mol 00971 0 2 180 Aspirin mol 1 g 75 1 . . . . . ! " ! " g
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Show all your work and provide all calculated answers with the correct number of sig. fig. 3. In this lab, we will use the following reaction to synthesize aspirin. a. If a student uses 3.50 g of salycilic acid and 2.50 mL of acetic anhydride, what will be the limiting reagent for the reaction? (The density of acetic anhydride is 1.08 g/mL) Aspirin mol 0264 0 A.A. mol 1 Aspirin mol 1 A.A. mol 0264 0 A.A. mol 0264 0 1 102 A.A. mol 1 mL 1 A.A. g 08 1 A.A. mL 50 2 Aspirin
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Unformatted text preview: mol 0253 S.A. mol 1 Aspirin mol 1 S.A. mol 0253 S.A. mol 0253 1 138 S.A. mol 1 S.A g 50 3 . . . . . . . . . . . . ! " ! " " ! " ! " g g b. What is the theoretical yield (in grams)? Aspirin g 57 4 mol 1 Aspirin g 2 180 Aspirin mol 0253 . . . ! " c. How many grams of the excess reagent have not reacted? unreacted. S.A. g 11 mol 1 A.A. g 1 102 A.A. mol 0011 used) A.A.(NOT mol 0011 (used) A.A. mol 0253-(init) A.A. mol 0264 . . . . . . ! " ! d. If the students aspirin weights 5.08 g, is the aspirin completely dry? Calculate the percent yield and use it to help justify your answer. % 111 100 Aspirin 4.57g Exp Aspirin g 08 5 ! " % . OH O OH O O O CH 3 CH 3 O O OH O CH 3 O O H CH 3 + + Salicylic Acid (138.1 g/mol) Acetic Anhydride (102.1 g/mol) Aspirin (180.2 g/mol) Acetic Acid (60.1 g/mol) No, the Aspirin is probably not completely dry. The % yield is greater than 100%, suggesting there is still water in the product....
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Chem+102+Quiz+5+2010b+-+answers - mol 0253 S.A. mol 1...

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