Kinetics Worksheet Chem 116‐ 2013 Chapter 15 1. The decomposition of BrO3‐ follows the following reaction: a. Express the rate of the reaction with respect of each of the reactants and products b. A concentration –vs‐time curve of the reaction was determined from a kinetic experiment: 1. What is the average rate of the reaction over the first 1200s? 2. What is the instantaneous rate of the reaction at 800s? 3. How long is the first half life? 4. If the rate of appearance of H2O (l) is 2.50x10‐4s‐1, what is the rate of disappearance of Br‐ (aq) 2. Give the relative rates of disappearance of reactants and formation of products for the following reaction . a. What is the rate of the reaction with respect to [O2] b. If the rate of formation of O2 is 1.5x10‐3 mol/L*s. What is the rate of decomposition of O3? 3. How many half‐lives are required for the concentration of reactants to decrease to 25% its original value? 4. Determine the rate law and k for the following reaction: 5. decomposition of BrO3‐ follows the following reaction: The following data of initial rates was determined for the reaction above using different concentrations of reactants. Use the information given to answer the following: a. Determine the individual orders for all the reactants and the overall order b. Write the rate law for this reaction ________________________ c. Calculate the rate constant for this reaction: d. What will happen to the rate of the reaction of the concentration of [H2] is doubled e. What will be the initial rate of the reaction for Experiment #5? 6. Dinitrogen Pentoxide (N2O5), is not very stable. In the gas phase or dissolved in a non aqueous solvent like carbon tetrachloride. By the following reaction: 2N2O5Æ2N2O4 + O2. This reaction has a rate law of rate=k[N2O5]1. At 45ºC, the rate constant for the reaction in carbon tetrachloride is 6.22x10‐4 s‐1. a. If the initial concentration of N2O5 is 0.100M, how much time will it take for the concentration to drop to 0.0100M? b. If the initial concentration N2O5 in a carbon tetrachloride solution at 45ºC is 0.500M, what will be its concentration after 1hr? 7. The decomposition of Hydrogen Peroxide(H2O2) follows a first order reaction and has a rate constant of 7.30x10‐4 s‐1. Determine the percent of H2O2 that has decomposed in the first 500.0s after the reaction begins (Assume that at the beginning there is 100% of H2O2). 8. One of the most dangerous radioisotopes in nuclear explosions or accidents is iodine‐131, which concentrates in the thyroid gland. The half‐life of radioactive iodine‐131 is 8.0 days. What fraction of the initial iodine‐131 would be present after 24 days if none of it was eliminated though natural body process? 9. The decomposition of NO2 has a rate constant of 0.225 M‐1s‐1‐. a. What is the order of this reaction? What is the rate law for the reaction? b. How much (in g) NO2 remains after 4.00s if the initial concentration of NO2 (in 1.0L) is 1.33M? 10. Nitrosyl chloride, NOCl, decomposes slowly to NO and Cl2. The rate law for this reaction shows that the rate is second order in NOCl. The rate constant for the reaction is 0.020 M‐1s‐1 at a certain temperature. If the initial concentration of NOCl in a closed reaction vessel is 0.050 M, what will be the concentration after 30 minutes? 11. Calculate the activation Energy (Ea) for: k(45˚C)=5.79 x 10‐4 s‐1. (R=8.314 J/K*mol) , Given that k(25˚C) =3.46 x 10‐5 s‐1‐ and 12. The decomposition of di‐tert‐butyl peroxide is a first order reaction with a half‐life of 320 min at 135 ºC and 100min at 145 ºC. Calculate Ea for the reaction 13. The Arrhenius plot for the decomposition of hydrogen iodide looks like: a. What is Ea for this reaction? b. Estimate the value of k at 293ºC if the rate constant for the reaction is 3.02x10‐5 M‐1s‐1 at 356ºC