1 Z3 and Z4 only 2 Z4 only 3 Z2 only 4 Z3 only correct 5 Z1 only Explanation

1 z3 and z4 only 2 z4 only 3 z2 only 4 z3 only

This preview shows page 8 - 10 out of 10 pages.

1. Z3 and Z4 only 2. Z4 only 3. Z2 only 4. Z3 only correct 5. Z1 only Explanation: The overall order of the reaction rate is the sum of the orders of the reactants. 030 10.0points What is the rate constant for the first-order reaction 2 A B + C , if the concentration of A decreases to one- fourth its initial value in 38 min? Correct answer: 0 . 0364814 min 1 . Explanation: t = 38 min [A] t = 1 4 [A] 0 This is a first order reaction, so the rate expression is ln parenleftbigg [A] 0 [A] t parenrightbigg = k t . At t = 38 min, 4 = [A] 0 [A] t , so k = ln parenleftbigg [A] 0 [A] t parenrightbigg t = ln(4) 38 min = 0 . 0364814 min 1 . 031 10.0points The rate constant of the reaction between CO 2 and OH in aqueous solution to give the HCO 3 ion is 1 . 5 × 10 10 L mol · s at 25 C. What is the rate constant at 28 C, if the activation energy for the reaction is 38 kJ / mol? Correct answer: 1 . 52311 × 10 10 L mol · s . Explanation: T = 25 C = 298 K T = 28 C = 301 K k = 1 . 5 × 10 10 L mol · s E a = 38 kJ / mol Using the Arrhenius equation, E a = R ln parenleftbigg k k parenrightbigg 1 T - 1 T Rearranging to solve for k , ln parenleftbigg k k parenrightbigg = E a R parenleftbigg 1 T - 1 T parenrightbigg = 38 kJ / mol 0 . 08314 kJ K · mol × parenleftbigg 1 298 K - 1 301 K parenrightbigg ln parenleftbigg k k parenrightbigg = 0 . 0152866
Image of page 8
moore (jwm2685) – Homework 9 – vanden bout – (51640) 9 k k = e 0 . 0152866 = 1 . 0154 k = 1 . 0154 k = e 0 . 0152866 parenleftbigg 1 . 5 × 10 10 L mol · s parenrightbigg = 1 . 52311 × 10 10 L mol · s 032 10.0points Which statement is FALSE? 1. The half-life for a second-order reaction decreases with increasing initial concentra- tions. 2. The rate constant for a reaction is inde- pendent of temperature. correct 3. The rate law expression relates rate and concentration. 4. The reaction rate for a zero-order reaction is independent of concentrations. 5. The integrated rate equation relates time and concentration. Explanation: 033 10.0points A non-steroidal anti-inflammatory drug is me- tabolized with a first-order rate constant of 3.25 day 1 . What is the half-life for the metabolism reaction? 1. 2.25 day 2. 1.63 day 3. 0.213 day correct 4. 0.308 day Explanation: 034 10.0points A compound decomposes with a half-life of 8.0 s and the half-life is independent of the concentration. How long does it take for the concentration to decrease to one-ninth of its initial value? 1. 72 s 2. 64 s 3. 32 s 4. 3.6 s 5. 25 s correct Explanation: 035 10.0points For the reaction cyclobutane(g) 2 ethylene(g) at 800 K, a plot of ln[cyclobutane] vs t gives a straight line with a slope of - 1 . 6 s 1 . Calcu- late the time needed for the concentration of cyclobutane to fall to 1 16 of its initial value. 1. 1.6 s 2. 0.63 s 3. 1.3 s 4. 2.3 s 5. 1.7 s correct Explanation: 036 10.0points For the reaction A products , the following data were collected. time, s [A] t , M 0 1.00 1.00 0.430 2.00 0.270 3.00 0.200 4.00 0.160 What is the half-life for this reaction?
Image of page 9
moore (jwm2685) – Homework 9 – vanden bout – (51640) 10 1. 0.521 s 2. 1.08 s 3. 0.922 s 4. 0.752 s correct Explanation: 037 10.0points Consider the elementary reaction: BaCO 3 ( aq ) -→ CO 2 ( aq ) + BaO( s ) If k = 2 . 85 × 10 2 M · s 1 , and there is initially 1 M BaCO 3 , what is the half-life of the reaction?
Image of page 10

You've reached the end of your free preview.

Want to read all 10 pages?

  • Fall '07
  • Holcombe
  • Chemistry, Rate equation

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture