chapter13problemsb

chapter13problemsb - Final Examination Spring 2011.

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Unformatted text preview: Final Examination Spring 2011. Name___________________________________ R.Lopez de la Vega Bubble in the form number in the section entitled Grade or Educ in the scantron. MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Which of the elementary reactions shown above has a molecularity of one? A) elementary reaction (a) B) elementary reaction (b) C) elementary reaction (c) D) elementary reactions (a), (b), and (c) 1) 2) Which of the elementary reactions shown above has a molecularity of two? A) elementary reaction (a) B) elementary reaction (b) C) elementary reaction (c) D) elementary reactions (a), (b), and (c) 2) 3) Which of the elementary reactions shown above has a molecularity of three? A) elementary reaction (a) B) elementary reaction (b) C) elementary reaction (c) D) elementary reactions (a), (b), and (c) 3) 1 Consider a reaction that occurs by the following one-step mechanism: A2 + B2 → 2 AB The potential energy profile for this reaction is shown below. 4) What is the species present at reaction stage 1? A) a product C) an intermediate 4) B) a reactant D) a transition state Consider a reaction that occurs by the following mechanism: A + BC → AC + B AC + D → A + CD The potential energy profile for this reaction is shown below. 5) Intermediates occur at which reaction stages? A) reaction stages 1 and 5 C) reaction stage 3 5) B) reaction stages 2, 3, and 4 D) reaction stages 2 and 4 2 6) What is the activation energy for the formation of ozone? A) 14 kJ B) 406 kJ C) 392 kJ 6) D) none of these 7) What is the activation energy for the destruction of ozone? A) 392 kJ B) 14 kJ C) 406 kJ D) none of these 7) 8) For a particular first-order reaction, it takes 12 minutes for the concentration of the reactant to decrease to 25% of its initial value. What is the value for rate constant (in s-1) for the reaction? D) 1.2 × 10-1 s -1 A) 1.9 × 10-3 s -1 B) 4.0 × 10-4 s -1 C) 2.4 × 10-2 s -1 8) Consider a reaction that occurs by the following mechanism: A + BC → AC + B AC + D → A + CD The potential energy profile for this reaction is shown below. 9) Transition states occur at which reaction stages? A) reaction stages 1 and 5 C) reaction stages 2, 3, and 4 9) B) reaction stages 2 and 4 D) reaction stage 3 3 Consider a reaction that occurs by the following one-step mechanism: A2 + B2 → 2 AB The potential energy profile for this reaction is shown below. 10) What is the species present at reaction stage 3? A) a product C) an intermediate B) a transition state D) a reactant 10) 11) What is the species present at reaction stage 2? A) a reactant C) an intermediate B) a product D) a transition state 11) 12) The first-order reaction, SO2Cl2 → SO2 + Cl2, has a rate constant equal to 2.20 × 10-5 s -1 at 593 K. What percentage of the initial amount SO2Cl2 will remain after 2.00 hours? A) 1.00% B) 17.1% C) 14.7% D) 85.4% 12) 13) The first-order reaction, 2 N2O(g) → 2 N2(g) + O2(g), has a rate constant equal to 0.76 s -1 at 1000 K. How long will it take for the concentration of N2O to decrease to 6.0% of its initial concentration? A) 17 s B) 0.27 s C) 3.7 s D) 13 s 13) 14) The first-order reaction, SO2Cl2 → SO2 + Cl2, has a half-life of 8.75 hours at 593 K. How long will it take for the concentration of SO2Cl2 to fall to 20.5% of its initial value? A) 0.128 hr B) 20.0 hr C) 2.90 hr D) 7.81 hr 14) 15) In aqueous solution, hypobromite ion, BrO -, reacts to produce bromate ion, BrO3-, and bromide ion, Br-, according to the following chemical equation. 3 BrO-(aq) → BrO3-(aq) + 2 Br-(aq) 15) A plot of 1/[BrO-] vs. time is linear and the slope is equal to 0.056 M-1s-1. If the initial concentration of BrO- is 1.0 M, how long will it take one -half of the BrO- ion to react? A) 5.6 × 10-2 s B) 12 s C) 8.9 s D) 18 s 4 16) Nitrogen dioxide decomposes at 300°C via a second-order process to produce nitrogen monoxide and oxygen according to the following chemical equation. 2 NO2(g) → 2 NO(g) + O2(g). A sample of NO 2(g) is initially placed in a 2.50-L reaction vessel at 300°C. If the half-life and the rate constant at 300°C are 44 seconds and 0.54 M -1 s -1, respectively, how many moles of NO 2 were in the original sample? A) 24 mol B) 59 mol C) 0.042 mol D) 0.11 mol 16) 17) Hydrogen iodide decomposes at 800 K via a second-order process to produce hydrogen and iodine according to the following chemical equation. 2HI(g) → H2(g) + I2(g) At 800 K it takes 471 seconds for the initial concentration of HI to decrease from 4.75 × 10-2 M to 1.50 × 10-2 M. What is the rate constant for the reaction at this temperature? A) 4.65 × 10-5 M-1s-1 B) 9.68 × 10-2 M-1s-1 17) C) 2.15 × 104 M-1s-1 D) 10.3 M-1s-1 18) The aquation of tris(1,10 -phenanthroline)iron(II) in acid solution takes place according to the equation: Fe(phen)32+ + 3 H3O+ + 3 H2O → Fe(H2O)62+ + 3 phenH+. If the activation energy, Ea, is 126 kJ/mol and the rate constant at 30°C is 9.8 × 10-3 min-1, what is the rate constant at 50°C? A) 2.2 × 10-1 min-1 C) 4.6 × 100 min-1 B) 4.4 × 10-4 min-1 D) 2.3 × 103 min-1 19) The isomerization reaction, CH3NC → CH 3CN, is first order and the rate constant is equal to 0.46 s-1 at 600 K. What is the concentration of CH3NC after 0.20 minutes if the initial concentration is 0.10 M? A) 9.1 × 10-4 M 18) B) 4.0 × 10-2 M C) 9.1 × 10-2 M 5 D) 4.0 × 10-4 M 19) Answer Key Testname: UNTITLED1 1) B 2) A 3) C 4) B 5) C 6) B 7) B 8) A 9) B 10) A 11) D 12) D 13) C 14) B 15) D 16) D 17) B 18) A 19) D 6 ...
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