608 Chapter 13 - Chemical Kinetics (a) Determine the order of the reaction. b) Calcu- late the rate constant. (c) Suggest a plausible mecha- nism that is consistent with the rate law. (Hint: Assume that the oxygen atom is the intermediate.) Additional Problems 13.67 The following diagrams represent the progress of the reaction A-B, where the red spheres represent A molecules and the green spheres represent B mole- cules. Calculate the rate constant of the reaction. ki- av- 13.75 When methyl phosphate is heated in acid solution, it of reacts with water: e, a If the reaction is carried out in water enriched with O, the oxygen-18 isotope is found in the phosphoric acid product but not in the methanol. What does this tell us about the mechanism of the reaction? CH,ОРО,Н, + Н,О — СН,ОН + HРО, hly e's de- ere. t= 0 s t = 20 s t = 40 s 13.68 The following diagrams show the progress of the reac- tion 2A A2. Determine whether the reaction is first order or second order and calculate the rate constant. the uit. 13.76 The rate of the reaction ake ntil r of CH;COOC,H;(aq) + H2O(l) CH;COOH(aq) + C,H;OH(aq) 00? shows first-order characteristics-that is, rate = k[CH;COOC,Hs]-even though this is a second- order reaction (first order in CH;COOC,H5 and first order in H,O). Explain. t = 0 min 13.77 Which of the following equations best describes the t = 15 min t = 30 min diagram shown: (a) A – B, (b) A 3B, (c) 3A → B? 13.69 Suggest experimental means by which the rates of the following reactions could be followed: (a) CaCO3(s) → CaO(s) + CO2(g) (b) Cl2(g) +2Br (aq) Br,(aq) +2CI¯(aq) (c) C,H6(g) → C2H4(g) + H2(g) (d) C,H5I(g) + H,O(1) СНОН (ад) + H'"(aq) + I(аg) 13.70 List four factors that influence the rate of a reaction. 13.71 "The rate constant for the reaction NO2(8) + CO(g) → NO(8) + C02(g) (S) is 1.64 x 10-%IM s." What is incomplete about this 23.15 The reaction 2A + 3B C is first order with re- spect to A and B. When the initial concentrations are [A] = 1.6 xX 10-M and [B] = 2.4 x 10M, the rate is 4.1 x 10* M/s. Calculate the rate constant of statement? 13.72 In a certain industrial process involving a heteroge- neous catalyst, the volume of the catalyst (in the shape of a sphere) is 10.0 cm. Calculate the surface area of the catalyst. If the sphere is broken down into eight spheres, each having a volume of 1.25 cm', what is the total surface area of the spheres? Which of the two geometric configurations of the catalyst is more effective? (The surface area of a sphere is 4ar, where r is the radius of the sphere.) Based on your analysis here, explain why it is sometimes dangerous to work in grain elevators. 13.73 Use the data in Example 13.5 to determine graphi- %3D the reaction. 13.79 The bromination of acetone is acid-catalyzed: CH3COCH3 + Br2 catalyst н* CH3COCH,Br + H* + Br The rate of disappearance of bromine was measured for several different concentrations of acetone, bro- mine, and H* ions at a certain temperature: 6. Rate of cally the half-1life of the reaction. Disappearance [H*] of Br2 (MIs) [CH3COCH3] [Br2] 13.74) The following data were collected for the reaction between hydrogen and nitric oxide at 700°C: (1) 0.30 0.050 0.050 5.7 X 10 5 5.7 x 10-5 2H,(g) + 2NO(g) 2H,0(g) + N2(8) (2) 0.30 0.10 0.050 (3) (4) 0.30 0.050 0.20 1.2 x 10-4 3.1 X 10 4 7.6 X 10-5 0.40 0.050 0.20 Experiment [H2] [NO] Initial Rate (M/s) (5) 0.40 0.050 0.050 0.010 0.025 2.4 x 10-6 (a) What is the rate law for the reaction? (b) Determine the rate constant. (c) The following mechanism has 0.0050 0.025 1.2 x 10-6 3 0.010 0.0125 0.60 x 10-6 been proposed for the reaction: Concentration