1. Slide 1 of 61 14-4 Zero-Order Reactions A → products R rxn = k [A] 0 R rxn = k [k] = mol L -1 s -1

2. Slide 2 of 61 Integrated Rate Law -- dtdt= k d[A]  [A] 0 [A] t 0 t -[A] t + [A] 0 = kt [A] t = [A] 0 - kt ΔtΔt -Δ[A] dtdt = k -d[A] Move to the infinitesimal = k And integrate from 0 to time t

3. Slide 3 of 61 14-5 First-Order Reactions H 2 O 2 (aq) → H 2 O(l) + ½ O 2 (g) = -k[H 2 O 2 ] d[H 2 O 2 ] dtdt = - k dt [H 2 O 2 ] d[H 2 O 2 ]  [A] 0 [A] t  0 t = -kt ln [A] t [A] 0 ln[A] t = -kt + ln[A] 0 [k] = s -1

4. Slide 4 of 61 First-Order Reactions

5. Slide 5 of 61 Half-Life  t ½ is the time taken for one-half of a reactant to be consumed. = -kt ln [A] t [A] 0 = -kt ½ ln ½[A] 0 [A] 0 - ln 2 = -kt ½ t ½ = ln 2 k 0.693 k =

6. Slide 6 of 61 Half-Life Bu t OOBu t (g) → 2 CH 3 CO(g) + C 2 H 4 (g)

7. Slide 7 of 61 Some Typical First-Order Processes

8. Slide 8 of 61 14-6 Second-Order Reactions  Rate law where sum of exponents m + n + … = 2. A → products dtdt= - k d[A] [A] 2  [A] 0 [A] t  0 t = kt + 1 [A] 0 [A] t 1 dtdt = -k[A] 2 d[A] [k] = M -1 s -1 = L mol -1 s -1

9. Slide 9 of 61 Second-Order Reaction

10. Slide 10 of 61 Testing for a Rate Law Plot [A] vs t.Plot ln[A] vs t.Plot 1/[A] vs t.

11. Slide 11 of 61 14-7 Reaction Kinetics: A Summary  Calculate the rate of a reaction from a known rate law using:  Determine the instantaneous rate of the reaction by: Rate of reaction = k [A] m [B] n …. Finding the slope of the tangent line of [A] vs t or, Evaluate –Δ[A]/Δt, with a short Δt interval.

12. Slide 12 of 61 Summary of Kinetics  Determine the order of reaction by: Using the method of initial rates. Find the graph that yields a straight line. Test for the half-life to find first order reactions. Substitute data into integrated rate laws to find the rate law that gives a consistent value of k.

13. Slide 13 of 61 Summary of Kinetics  Find the rate constant k by:  Find reactant concentrations or times for certain conditions using the integrated rate law after determining k. Determining the slope of a straight line graph. Evaluating k with the integrated rate law. Measuring the half life of first-order reactions.

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15. Slide 15 of 61  Worked Examples Follow:

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20. Slide 20 of 61  CRS Questions Follow:

21. Slide 21 of 61 In the diagram to the right is a plot of the concentrations of all reactants and products as a function of time for a particular reaction. ln [X] t Which of the following statements is correct? 5. Cannot tell with the information given. 1. The reaction is second order. 2. The blue curve represents the time dependence on a particular product. 3. The rate constant for the reaction could have units of s -1. 4. The product represented by the green line is produced almost twice as fast as the product represented by the red line.

22. Slide 22 of 61 In the diagram to the right is a plot of the concentrations of all reactants and products as a function of time for a particular reaction. ln [X] t Which of the following statements is correct? 5. Cannot tell with the information given. 1. The reaction is second order. 2. The blue curve represents the time dependence on a particular product. 3. The rate constant for the reaction could have units of s -1. 4. The product represented by the green line is produced almost twice as fast as the product represented by the red line.

23. Slide 23 of 61 Reaction A has a rate constant which is equal to 16.2 L mol -1 s -1. A plot relating the concentrations of the reactants and products with time is plotted for reaction B to the right. ln [X] t In this question, two reactions are considered. 1.Reaction A is first order and Reaction B is second order. 2. Reaction A is second order and Reaction B is first order. 3. Both reactions are first order. 4. Both reactions are second order.

24. Slide 24 of 61 Reaction A has a rate constant which is equal to 16.2 L mol -1 s -1. A plot relating the concentrations of the reactants and products with time is plotted for reaction B to the right. ln [X] t In this question, two reactions are considered. 1.Reaction A is first order and Reaction B is second order. 2. Reaction A is second order and Reaction B is first order. 3. Both reactions are first order. 4. Both reactions are second order.

25. Slide 25 of 61 81.7 s Some data for the decomposition of dinitrogen pentoxide are plotted to the right. Which of the following statements is correct? 1. The rate constant is 81.7 s. 3. The units of the rate constant are s. 4. The reaction is first order in N 2 O 5. 5. The reaction is third order in N 2 O 5. 2. The rate constant is

26. Slide 26 of 61 81.7 s Some data for the decomposition of dinitrogen pentoxide are plotted to the right. Which of the following statements is correct? 1. The rate constant is 81.7 s. 3. The units of the rate constant are s. 4. The reaction is first order in N 2 O 5. 5. The reaction is third order in N 2 O 5. 2. The rate constant is