15. Figure 12.1 p. 562 Definition of Rate. 2NO 2  2NO + O 2

20. At .90 M the rate is - (.98 - .76) = -0.22 = 5.5x 10 -4 M• s -1 (0-400) -400

21. At .45 M the rate is - (.52 - .31) = -0.22 = 2.7 x 10 -4 (1000-1800) -800

41. Figure 12.4 A Plot of In (N 2 O 5 ) Versus Time (1st order)

43. Figure 12.5: A Plot of (N 2 O 5 ) vs. Time for the Decomposition Reaction of N 2 O 5

51. Z7e 546 Figure 12.7 A Plot of [A] Versus t for a Zero-Order Reaction

53. Fig. 12.8 Decomposition Reaction N 2 O  2N 2 + O 2 Even though [N 2 O] is twice as great in (b) as in (a) the reaction occurs on a saturated platinum surface, so rate is zero order

54. Zero Order Graph Time Concentration

55. Zero Order Graph Time Concentration  A]/  t = slope  t -k =  A] t 1/2 = [A 0 ]/2k

62. Use for Online HW pp Use for online HW Hint: on one problem you will have to first determine the order , then use the half-life equation (5 th line) to solve for k, then use the Integrated rate law (2 nd line) to solve for time (t).

64. Figure 12.9 A Molecular Representation of the Elementary Steps in the Reaction of NO 2 and CO Overall: NO 2 + CO  NO + CO 2 Step 1: NO 2 + NO 2  NO 3 + NO (k 1 ) Step 2: NO 3 + CO  NO 2 + CO 2 (k 2 ) NO 3 is an intermediate

80. Potential Energy Reaction Coordinate Reactants Products

81. Potential Energy Reaction Coordinate Reactants Products Activation Energy E a

82. Potential Energy Reaction Coordinate Reactants Products Activated complex

83. Potential Energy Reaction Coordinate Reactants Products  E }

84. Potential Energy Reaction Coordinate 2BrNO 2NO + Br Br---NO Br---NO 2 Transition State

88. Figure 12.13 Several Possible Orientations for a Collision Between Two BrNO Molecules. (a) & (b) can lead to a collision, (c) cannot.

89. No Reaction O N Br O N Br O N Br O N Br O N Br O N Br O N Br O N Br O N Br O N Br

91. Figure 12.14 pp Plot of In( k ) vs. 1/ T for 2N 2 O 5( g )    g ) + O 2( g ). Can get E a from slope = -E a /R Do in lab 12.

92. Figure 12.14 Plot of In( k ) vs. 1/ T for 2N 2 O 5( g )    g ) + O 2( g ). Can get E a from slope = -E a /R Do in lab 12.

93. Activation Energy and Rates The final saga

97. Second step is slow High activation energy E a

98. E a Third step is fast Low activation energy

99. Second step is rate determining

100. Intermediates are present

101. Activated Complexes or Transition States

104. Figure 12.15 Energy Plots for a Catalyzed and an Uncatalyzed Pathway for a Given Reaction. ∆ E is the same in both cases.

105. Figure 12.16 Effect of a Catalyst on the Number of Reaction-Producing Collisions (increases even though no temperature increase).

107. Heterogenous Catalysts Pt surface H H H H C H H C H H

110. Heterogenous Catalysts Pt surface H C H H C H H H H H