CHE 321 Organic Chemistry 1 Exam 1 Form 1 Thursday September 18, 2014 1. Write your nine digit University ID number in the space provided and then bubble in each of the nine digits. 2. Print your name and sign your answer form using the spaces provided. 3. Questions 1 to 10 are 3 point multiple choice questions. Questions 11‐14 are 5 point multiple choice questions. Bubble your answers on the answer form. Questions 15‐21 are short answer questions with points as indicated. Write out your answers in the indicated place on the answer form. OH
Br
R
O
PCC
OR or OH
R
R(H)
OH
HBr
R(H)
O
1.
Li
Br
Li
R1
R2
OH
Li
2. H2O
R1 R 2
H2
Pd
Br
CHE 321 Organic Chemistry I Exam 1 – Form 1 Page 2 of 7 For each of the following choose the stronger acid. (3 points each) From Workshop 3 and Pre‐Class Quiz 6 O
1.
O
H
CH3
A
B
O
O
CH3
2.
N
CH3
A
B
O
3.
CH3
O
S
H
A
O
H
B
For each of the following choose the stronger base. (3 points each) ) From Workshop 3 and Pre‐Class Quiz 6 CHE 321 Organic Chemistry I Exam 1 – Form 1 Page 3 of 7 6,7,8. A student had three samples of unknown compounds of the formula C5H10O2, with the possible structures shown below. An IR was obtained for each sample. Idenitify each sample. (3 points each) From Pre‐Class Quiz 5 Workshope Exercise 2 OH
O
O
OH
A
O
B
O
O
H
O
OH
O
C
O
D
O
E
F
6 6 D 7 F 8 E CHE 321 Organic Chemistry I Exam 1 – Form 1 Page 4 of 7 Five different protonation states of the amino acid valine are shown below. Use these structures to answer the next two questions. The pKa of the NH4+ group is 9.7. The pKa of the CO2H group is 2.3. (3 points each) From Workshop 3 9. Which structure represents the predominate form of valine dissolved in pure water? E 10. Which structure represents the predominate form of valine dissolved in a buffered solution of pH = 2? B 11. The following reaction gives a compound called a hemiacetal. The arrows show the first step of the reaction. Follow the arrows and choose the structure of the intermediate. (5 points) Pre‐class quiz 1 12. The pKa of HF is 3.2. What is the ΔG° for the acid dissociation? (5 points) From Pre‐Class Quiz 2 A. ‐18.2 kJ/mol B. ‐5.7 kJ/mol C. ‐3.2 kJ/mol D 3.2 kJ/mol E 5.7 kJ/mol F 18.2 kJ/mol CHE 321 Organic Chemistry I Exam 1 – Form 1 Page 5 of 7 13. Choose the structure that is not a contributing (resonance) structure of compound X. (5 points) From Workshop Exercise 1 14. Choose the order that has the following compounds correctly arranged with respect to increasing solubility in water. (5 points) From Workshop 2 H
N
NH2
i
A
i ii iii
increasing
solubility
i iii ii
B increasing
solubility
ii
ii i iii
increasing
C
solubility
N
iii
D
ii iii i
increasing
solubility
iii ii i
increasing
E
solubility
iii i ii
increasing
F
solubility
______________________________
Write out your answers to the following short answer questions in their indicated places on the answer form. 15. Give the structure of one compound that meets all of the following criteria. There is more than one correct answer. (5 points) From Workshop Exercise 2 a. Has a molecular formula of C5H8O. b. Has exactly 4 sp3 hybridized carbon atoms and 1 sp2 hybridized carbon atom. c. The IR spectrum shows a strong peak at ~1700 cm‐1. CHE 321 Organic Chemistry I Exam 1 – Form 1 Page 6 of 7 16. Draw the product of the following reaction. (5 points) Pre‐Class Quiz 10 17. Draw the structure of protonated benzamide. (5 points) Pre‐Class Quiz 4 Only one structure needed
18. The following cation has several contributing (resonance) structures. Draw the best contributing structure of the following cation, showing all lone pairs and any formal charges. (5 points) Pre‐Class Quiz 4 19. Draw a curved arrow mechanism for the deprotonation reaction shown below. Clearly show all bond making and bond breaking steps. Be sure to show the product in its most stable resonance form. Pre‐Class Quiz 3 Hint: Before beginning choose the most acidic H atom. (10 points) CHE 321 Organic Chemistry I Exam 1 – Form 1 Page 7 of 7 20. Draw a curved arrow mechanism for the elimination reaction shown below. Clearly show all bond making and bond breaking steps. (10 points) Pre‐Class Quiz 8 21. Using the library of synthetic reactions above, propose a synthesis of the following compound from compounds containing four carbon atoms or less. (10 points) Pre‐Class Quiz 9 Workshop Exercise 3