Chapter 6
1. Calculate the enthalpy of the following reaction.
I+HBr Br +HI
2. Calculate the enthalpy of the following reaction.
+I2+HI
I
3. Calculate the enthalpy of the following reaction.
+H2O+HF
OH
F
4. Which of the following is the enthalpy of the following reaction?
I+HBr Br +HI
A. -8 kJ/mol
B. 8 kJ/mol
C. 222 kJ/mol
D. 79 kJ/mol
5. Which of the following is the enthalpy of the following reaction?
+H2O+HF
OH
F
A. -8 kJ/mol
B. 8 kJ/mol
C. -506 kJ/mol
D. 63 kJ/mol
6. What type of cleavage does the following reaction involve?
HOOH 2 HO
A. homolytic
B. heterolytic
7. What type of cleavage does the following reaction involve?
Br +Br
8. Predict the sign of S of the following reaction?
N3
+N
N
N
A. positive
B. negative
C. no change
9. Predict the sign of S of the following reaction?
Br +HBr
A. positive
B. negative
C. no change
10. Predict the sign of S of the following reaction?
A. positive
B. negative
C. no change
11. Predict the sign of S of the following reaction?
O
OH
12. Why is entropy negative for ring closures?
A. Closing a ring results in fewer molecules.
B. Closing a ring results in more molecules.
C. Closing a ring releases energy.
D. Closing a ring restricts the rotation around individual carbon-carbon bonds.
13. Which of the following would you expect to have the most negative S?
OH OOH
OH
A. B.
C. D. OH
O
OO
14. Predict the sign of G for an exothermic reaction with an increase in entropy.
A. positive
B. negative
C. no change
D. cannot predict
15. Predict the sign of G for an endothermic reaction with an increase in entropy.
A. positive
B. negative
C. no change
D. cannot predict
16. Predict the sign of G for an exothermic reaction with a decrease in entropy.
A. positive
B. negative
C. no change
D. cannot predict
Difficulty Level: Easy
17. Predict the sign of G for an endothermic reaction with a decrease in entropy.
A. positive
B. negative
C. no change
D. cannot predict
18. Does a reaction with a positive G favor reactants or products?
19. Does a reaction with a negative G favor reactants or products?
20. Does a reaction with a positive S and a positive H favor reactants or products?
21. Does a reaction with a positive S and a negative H favor reactants or products?
22. Does a reaction with a Keq = 10 favor reactants or products?
Difficulty Level: Hard
23. Does a reaction with a H of 14 kJ/mol and a S of 150 J/molK at 298 K favor
reactants or products?
24. Does a reaction with a H or 20 kJ/mol and a S of 10 J/mol K at 298 K favor
reactants of products?
25. Given the following rate law, the reaction is what order in MeI?
Rate = k[MeI][NaCN]
26. Given the following rate law, the reaction is what order in tert-butyliodide?
Rate = k [ ]
I
27. Given the following rate law, the reaction is what order in sodium cyanide?
Rate = k[MeI][NaCN]2
28. What is the energy of activation for the following reaction?
29. What is the energy of activation for the following reaction?
30. Based on the following energy diagram, is the following reaction exothermic or
endothermic?
31. Based on the following energy diagram, is the following reaction exothermic or
endothermic?
32. What is the effect of a catalyst on a reaction?
A. It speeds up the rate.
B. It decreases the entropy.
C. It changes the equilibrium.
D. It makes the products more stable.
33. Which of the following describes the effect of a catalyst on a reaction?
A. It lowers the free energy of the products.
B. It makes the reactants less stable.
C. It changes the equilibrium constant.
D. It lowers the energy of activation.
34. Which of the following is an energy diagram for a three step reaction?
35. Which of the following is an energy diagram for a two step reaction?
36. Draw an energy diagram for an endothermic reaction with two steps.
37. Draw an energy diagram for a three step reaction.
38. Draw an energy diagram for an exothermic concerted reaction.
39. Which of the following energy diagrams shows a concerted endothermic reaction?
40. Which of the following energy diagrams shows the reaction with the smallest energy
of activation?
41. What is a transition state?
A. An isolable intermediate in a reaction.
B. The starting materials of the reaction.
C. A local maximum on the energy diagram.
D. A point between the starting materials and the product.
42. What is an intermediate?
A. A local maximum on the energy diagram.
B. A point on the reaction pathway that has a discrete lifetime.
C. A point half-way between the starting materials and products.
D. The highest energy compound on an energy diagram.
43. Which of the following energy diagrams is of a reaction with one transition state?
44. Which of the following energy diagrams is of a reaction with one intermediate?
45. Identify the nucleophilic atom in the following molecule.
O
46. Identify the nucleophilic atom in the following molecule.
O
47. Identify the nucleophilic atom(s) in the following molecule.
N
H
O
48. Identify the nucleophilic centers in the following molecule.
49. Identify the nucleophilic centers in the following molecule.
Br
50. Identify the nucleophilic atom in the following molecule.
Me3P
A. P
B. C
C. H
D. Me
51. Identify the electrophilic atom in the following molecule.