A second-order reaction has a rate constant of 0.009000/(M · s) at 30°C. At 40°C, the rate constant is 0.02300/(M · s). (A) What is the activation energy for this reaction? _____kJ/mol (B) What is the frequency factor, A? ______ /(M · s) (C) Predict the value of the rate constant at 72°C. _____ /(M · s)

Hydrogen iodide, HI, decomposes in the gas phase to produce hydrogen, H2, and iodine, I2. The value of the rate constant, k, fur the reaction was measured at several different temperatures and the data are shown here: Temperature (K) k (M -1 5-1) 555 6.23107 575 2.42106 645 1.44104 700 2.01103 What is the value of the activation energy (in kJ/mol) for this reaction?

The hydrolysis of the sugar sucrose to the sugars glucose and fructose, C12H22O11+H2OC6H12O6+C6H12O6 follows a first-order rate equation for the disappearance of sucrose: Rate =k[C12H22O11] (The products of the reaction, glucose and fructose, have the same molecular formulas but differ in the arrangement of the atoms in their molecules.) (a) In neutral solution, k=2.11011s1 at 27 C and 8.51011s1 at 37 C. Determine the activation energy, the frequency factor, and the rate constant for this equation at 47 C (assuming the kinetics remain consistent with the Arrhenius equation at this temperature). (b) When a solution of sucrose with an initial concentration of 0.150 M reaches equilibrium, the concentration of sucrose is 1.65107M . How long will it take the solution to reach equilibrium at 27 C in the absence of a catalyst? Because the concentration of sucrose at equilibrium is so low, assume that the reaction is irreversible. (c) Why does assuming that the reaction is irreversible simplify the calculation in pan (b)?

(Section 11-5) A rule of thumb is that for a typical reaction, if concentrations are unchanged, a 10-K rise in temperature increases the reaction rate by two to four times. Use an average increase of three times to answer the questions below. (a) What is the approximate activation energy of a typical chemical reaction at 298 K? (b) If a catalyst increases a chemical reactions rate by providing a mechanism that has a lower activation energy, then what change do you expect a 10-K increase in temperature to make in the rate of a reaction whose uncatalyzed activation energy of 75 kJ/mol has been lowered to one half this value (at 298 K) by addition of a catalyst?

Give at least two physical properties that might be used to determine the rate of a reaction.

Derive expressions for the half-life of zero-, first-, and second-order reactions using the integrated rate law for each order. How does each half-life depend on concentration? If the half- life for a reaction is 20. seconds, what would be the second half-Life assuming the reaction is either zero, first, or second order?

The decomposition of azomethane, (CH3)2N2, to nitrogen and ethane gases is a first-order reaction, (CH3)2N2(g)N2(g)+C2H6(g). At a certain temperature, a 29-mg sample of azomethane is reduced to 12 mg in 1.4 s. (a) What is the rate constant k for the decomposition at that temperature? (b) What is the half-life of the decomposition? (c) How long will it take to decompose 78% of the azomethane?

Kinetics II You and a friend are working together in order to obtain as much kinetic information as possible about the reaction A(g)B(g)+C(g). One thing you know before performing the experiments is that the reaction is zero order, first order, or second order with respect to A. Your friend goes off, runs the experiment, and brings back the following graph. a After studying the curve of the graph, she declares that the reaction is second order, with a corresponding rate law of Rate = k[A]2. Judging solely on the basis of the information presented in this plot, is she correct in her statement that the reaction must be second order? Here are some data collected from her experiment: Time (s) [A] 0.0 1.0 1.0 0.14 3.0 2.5 103 5.0 4.5 105 7.0 8.3 107 b The half-life of the reaction is 0.35 s. Do these data support the reaction being second order, or is it something else? Try to reach a conclusive answer without graphing the data. c What is the rate constant for the reaction? d The mechanism for this reaction is found to be a two-step process, with intermediates X and Y. The first step of the reaction is the rate-determining step. Write a possible mechanism for the reaction. e You perform additional experiments and find that the rate constant doubles in value when you increase the temperature by 10oC. Your lab partner doesnt understand why the rate constant changes in this manner. What could you say to your partner to help her understand? Feel free to use figures and pictures as part of your explanation.

Regular ?ights of supersonic aircraft in the stratosphere ale of concern because such aircraft produce nitric oxide, NO, as a byproduct in the exhaust of their engines. Nitric oxide reacts with ozone, and it has been suggested that this could contribute to depletion of the ozone layer. The reaction NO+O3NO2+O2 is first order with respect to both NO and O3 with a rate constant of 2.20107 L/mol/s. What is the instantaneous rate of disappearance of NO when [NO]=3.3106 M and [O3]=5.9107M?

The reaction 2 NO(g) + 2 H2(g) N2(g) + 2 H2O(g) was studied at 904 C, and the data in the table were collected. (a) Determine the order of the reaction for each reactant. (b) Write the rate equation for the reaction. (c) Calculate the rate constant for the reaction. (d) Find the rate of appearance of N2 at the instant when [NO] = 0.350 mol/L and [H] = 0.205 mol/L.