s 1 correct 4 4 6 M 2 s 1 5 22 M 2 s 1 Explanation 021 100 points Under certain

S 1 correct 4 4 6 m 2 s 1 5 22 m 2 s 1 explanation

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· s 1 correct 4. 4 . 6 M 2 · s 1 5. 22 M 2 · s 1 Explanation: 021 10.0 points Under certain conditions, the reaction 3 A + 2 B 4 C was observed to proceed at a rate of 0 . 00158 M · s 1 . What was the corresponding rate of change in reactant A? 1. - 0 . 00316 M · s 1 2. 0 . 00474 M · s 1 3. - 0 . 00158 M · s 1 4. - 0 . 00079 M · s 1
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kamalska (mk23835) – HW03 – Quigley – (104001) 7 5. - 0 . 000526667 M · s 1 6. 0 . 00158 M · s 1 7. - 0 . 00474 M · s 1 correct 8. 0 . 000526667 M · s 1 9. 0 . 00316 M · s 1 10. 0 . 00079 M · s 1 Explanation: Reactant A is reacting at 3 times the stated rate of the overall reaction. A is also a reac- tant, so the concentration is DECREASING with time, which corresponds to a NEGA- TIVE rate. 022 10.0 points For the reaction A B the initial concentration of [A] is 0.1 M. How much of compound [A] is left after 60 minutes if k = 4 . 2 × 10 6 s 1 ? 1. 8 . 5 × 10 2 2. 1 . 0 × 10 1 3. 9 . 8 × 10 2 correct 4. 4 . 1 × 10 1 5. 3 . 2 × 10 2 Explanation: 023 10.0 points Consider the following reaction 2 N 2 O(g) 2 N 2 (g) + O 2 (g) rate = k [N 2 O] . For an initial concentration of N 2 O of 0.50 M, calculate the concentration of N 2 O re- maining after 2.0 min if k = 3 . 4 × 10 3 s 1 . 1. 0.33 M correct 2. 0.17 M 3. 0.50 M 4. 0.66 M 5. 0.55 M Explanation: 024 10.0 points The reaction between nitrogen dioxide and carbon monoxide is thought to occur by the following mechanism: 2 NO 2 (g) NO 3 (g) + NO(g) k 1 , slow NO 3 (g) + CO(g) NO 2 (g) + CO 2 (g) k 2 , fast What is the rate law for this mechanism? 1. rate = k 1 k 2 [NO 2 ] 2 [CO] 2. rate = k 1 k 2 [NO 2 ] 2 [CO] 3. rate = k 2 [NO 3 ] [CO] 4. rate = k 1 [NO 2 ] 2 correct 5. rate = k 1 [NO 3 ] [NO] Explanation: 025 10.0 points Consider the mechanism NO 2 + F 2 NO 2 F + F k 1 , slow F + NO 2 NO 2 F k 2 , fast What is the rate law? 1. rate = k 2 [NO 2 ] 2 2. rate = k 2 [NO 2 ] [F] 3. rate = k 1 [NO 2 ] [F 2 ] correct 4. rate = k 1 k 2 [NO 2 ] 2 5. rate = k 1 [NO 2 F] [F] Explanation: 026 10.0 points
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kamalska (mk23835) – HW03 – Quigley – (104001) 8 The half-life of strontium-90 is 28.1 years. Calculate the percent of a strontium sample left after 100 years. 1. 8.5% correct 2. 76% 3. 0.34% 4. 63% 5. 82% Explanation: 027 10.0 points What is the rate law for the reaction A + B + C D if the following data were collected? Exp [A] 0 [B] 0 [C] 0 Initial Rate 1 0.4 1.2 0.7 2 . 32 × 10 3 2 1.3 1.2 0.9 7 . 54 × 10 3 3 0.4 4.1 0.8 9 . 25 × 10 2 4 1.3 1.2 0.2 7 . 54 × 10 3 1. rate = 5 . 37 × 10 3 [A] 1 [B] 3 [C] 0 2. rate = 1 . 79 × 10 3 [A] 0 [B] 2 [C] 1 3. rate = 1 . 49 × 10 3 [A] 0 [B] 3 [C] 1 4. rate = 3 . 36 × 10 3 [A] 1 [B] 3 [C] 0 correct 5. rate = 4 . 48 × 10 3 [A] 1 [B] 2 [C] 1 Explanation: 028 10.0 points A catalyst affects reaction rates by 1. decreasing the activation energy. cor- rect 2. producing a high energy activated com- plex. 3. increasing the number of molecular colli- sions. 4. increasing the activation energy. 5. increasing the concentration of reac- tants. Explanation: A catalyst affects the rate of a reaction by providing a lower energy pathway (mech- anism) for the reaction. This decreases the activation energy of the reaction.
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  • Fall '08
  • QUIGLEY
  • Reaction, Chemical reaction, Rate equation

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