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Unformatted text preview: wetsel (zpw67) – Postlab 7 Aspirin Synthesis – lyon – (51900) 1 This printout should have 20 questions. Multiplechoice questions may continue on the next column or page – find all choices before answering. 001 10.0 points What is the relationship between absorbance and transmittance? What value of ab sorbance corresponds to 65.0% transmit tance? 1. Absorbance is the negative natural log of transmittance. A = ln(0 . 65) = 0.43. 2. Absorbance is one over transmittance. A = 1 . 65 = 1.5. 3. Absorbance is equal to transmittance for all values less than 1.0. A = 0.65 4. Absorbance is the negative log 10 of the transmittance. A = log 10 (0 . 65) = 0.19. 5. Absorbance is equal to one half the trans mittance squared. A = 1 2 × (0 . 65) 2 = 0.21. 002 10.0 points The rules of significant figures DO NOT apply to the answer for the question below. Consider the reaction 2 C 6 H 6 + 15 O 2 → 12 CO 2 + 6 H 2 O If a sample of benzene (C 6 H 6 ) is 91% pure and the combustion of benzene by the reaction has a 74% yield, how much water is produced from 0 . 23 mol of a sample of impure benzene? Answer in units of mol. 003 10.0 points Thomas poured 25 mL of 0.60 M HCl into a large bottle. He then added enough water so that the new (diluted) concentration was 0.10 M HCl. How much water did Thomas add? 1. 25 mL 2. 150 mL 3. 125 mL 4. 100 mL 5. 75 mL 6. 50 mL 004 10.0 points In the reaction 4 P 4 + 5 S 8 → 4 P 4 S 10 600 g of P 4 is mixed with 1300 g of S 8 . How many grams of P 4 S 10 can be produced, assuming 100% yield based on the limiting reagent? 1. 2 . 16 × 10 3 g 2. 1 . 80 × 10 3 g 3. 6 . 16 × 10 3 g 4. 4 . 62 × 10 2 g 5. 8 . 20 × 10 2 g 005 10.0 points Consider the reaction 2 H 2 O 2 → 2 H 2 O + O 2 ....
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 Spring '08
 leytner

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