1. List three factors that affect the rate of a reaction.
2. If the rate of a reaction is independent of the concentration of all reactants, then the order of the reaction is
(a) zero (b) 1st (c) 2nd (d) 3rd
3. For a first order reaction, the slope of a plot of ln[A] vs. time is
(a) k (b) -k (c) ln[A] (d) kt (e) 1/[A]
4. A reaction which is second order in one reactant and half order in the other reactant has an overall order of (a) 1 (b) 1.5 (c) 2 (d) 2.5 (e) 3
5. The mechanism for the following reaction has 3 steps:
C4H9Br + 2H2O ----> C4H9OH + Br- + H3O+
Mechanism:
1. C4H9Br ----> C4H9+ + Br- slow
2. C4H9+ + 2H2O ----> C4H9OH2+ fast
3. C4H9OH2+ + H2O ---> C4H9OH + H3O+ fast
The rate law predicted for this mechanism is:
(a) rate = K[C4H9Br] (b) rate = K[C4H9Br ] [H2O]2
(c) rate = K[C4H9+][Br-] (d) rate = K[C4H9Br][C4H9+]
6. Which of the following applies to a zero-order reaction?
(a) rate decreases as concentration decreases (b) rate increases as time
(c) rate is proportional to concentration (d) none of the above
7. For a second order reaction
(a) k has units of mol2/L2 x time2 (b) 1/conc. vs time is a linear plot
(c) the half life = .693/k (d) rate does not change with time
8. The half-life for a first-order reaction is 32.0 sec. What was the original concentration if, after 2.0 minutes, the reactant concentration is .062M?
(a) .84M (b) .065 M (c) .091 M (d) .075 M
(Use the following rate law for question ( 9 - 12) Rate = k[A]2[B]
9. What happens to the rate, if the concentration of A doubles?
10. What happens to the rate, if [A] doubles and [B] decreases by a factor of four?
11. What happens to the rate, if the pressure on gases A and B doubles?
12. What happens to the rate, if a catalysts is added?
13. Given the following data write the rate law for the reaction, CF4 + H2 ---> CHF3 + HF
14. Calculate the rate constant for the reaction in question 13.
15. The decomposition of H2O2 is a first order reaction . If the initial concentration of hydrogen peroxide is 0.50 M, what is the concentration of the peroxide after 10 min.?
Given k = 0.0410/min.
16. Given the following data for the reaction 2A + B + C ---> 2D Determine the rate law for the reaction.
For Questions 17 :Given the reaction Tl+3 + 2Ru+3 ---> Tl+ + 2Ru+3
The rate of reaction data for the above reaction was plotted below in three different ways.
Y= [R+2] y=ln[R+2] y=1/[R+2]
Time Time Time
17. The above reaction is a
(a) 0 order (b) first order (c) second order
18. A certain 1st order reaction is 50% complete in 3.5 hours. How long will it take for the reaction to be 88% complete?
19.Chlorine atoms created by the flash photolysis of Cl2are observed to recombine according to a second order rate law. The first half-life is 10 milliseconds. How long will it take for the Cl atoms to decay to 1/8 of their initial concentration?
20. The rate constants for the reaction between CO and NO2 are known to 0.0521 s-1
at 15°c and 0.332 s-1 at 45°c. Calculate the activation energy for this reaction.
21. Explain how a catalyst affects a reaction rate.
Answers:
1) Temp. Concentration, Surface Area, Catalyst
2. A
3. B
4, D
5. A
6. D
7. B
8. A
9. 4X
10. same
11. 8x
12. faster
13. Rate = K[CF4]1[H2]1
14. 4500
15. .33
16. Rate = K[A]2[B]3 [C]1
17. B
18. 10.7 hr
19 70 msec