Chem 2312-003 Midterm II F‘12 Page 1 of 7 Chemistry 2312-003 Organic Chemistry I Midterm Examination II 11:00 am – 12:20 pm Form A November 1, 2012 J. Jeon Name: ____________________________________ Total /110 please print ID #: ______________________________________ • There are 110 points on this exam and the seven exam pages. • For the multiple choice questions 1-14, select the best answer and darken completely with a pencil the space corresponding to that answer in scantron (form # 882-E). • You are free to use molecular models during the exam. • For questions 15 and 16, I will not reconsider grades for answers written in pencil. Have fun!
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Chem 2312-003 Midterm II F‘12
Page 1 of 7
Chemistry 2312-003
Organic Chemistry I
Midterm Examination II 11:00 am – 12:20 pm
Form A
November 1, 2012
J. Jeon
Name: ____________________________________ Total /110 please print
ID #: ______________________________________
• There are 110 points on this exam and the seven exam pages. • For the multiple choice questions 1-14, select the best answer and darken completely with
a pencil the space corresponding to that answer in scantron (form # 882-E). • You are free to use molecular models during the exam. • For questions 15 and 16, I will not reconsider grades for answers written in pencil.
Have fun!
Chem 2312-003 Midterm II F‘12
Page 2 of 7
1-2. (10 pts) These problems are about the IUPAC (International Union of Pure and Applied Chemistry) nomenclature of organic compounds.
1. (5 pts) Select the best name for the following molecule.
Cl
a) (S)-5-Chloro-2,2-dimethylhexane b) (R)-2,2-Dimethy-5-chlorolhexane c) (2S,5R)-2,2-Dimethy-5-chlorolhexane d) (2R,5S)-2-Chloro-5,5-dimethylhexane e) (R)-5-Chloro-2,2-dimethylhexane
2. (5 pts) Select the best name for the following molecule.
F
a) (E)-3-Ethyl-5-fluorohept-5-ene b) (Z)-5-Ethyl-3-fluorohept-2-ene c) (E)-5-Ethyl-3-fluorohept-2-ene d) (Z)-3-Ethyl-5-fluorohept-5-ene e) (E)-3-Fluoro-5-ethylhept-5-ene
3-6. (20 pts) Label each of the following pairs of structures as “constitutional isomers (C)”, “diastereomers (D),” “enantiomers (E),” or “superimposable (S).”
3. (5 pts)
EtO2C
Cl
Cl
CO2Et CO2Et
Cl
Cl
EtO2C
a) C b) D c) E d) S
4. (5 pts)
Me
NH2Me
BrMe
NH2Br
Me
a) C b) D c) E d) S
5. (5 pts)
OH
Me NH2
MeH
Me
H2N OH
a) C b) D c) E d) S
6. (5 pts)
O O
a) C b) D c) E d) S
Chem 2312-003 Midterm II F‘12
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7. (5 pts) Designate R or S configuration for each of the chirality centers (A, B, and C).
A
B
C
NOH
Me MeH
A B C a) R S S b) S S R c) S R S d) R R S e) S R R
8. (5 pts) Which of the following compound(s) is (are) meso?
HPh
OHPhH
OH
same as HPh
OHHPh
OH
A AH
Cl CH3
HCl
CH3
B
a) A
b) B
c) All
d) none
9. (5 pts) Rank the following carbocations in order of stability. (1 = most stable, 4 = least stable)
A B C D
A B C D a) 4 1 3 2 b) 3 4 1 2 c) 1 3 4 2 d) 1 4 3 2 e) 3 4 2 1
10. (5 pts) Rank the following alkenes in order of stability. (1 = most stable, 4 = least stable)
A B C D
A B C D a) 2 4 3 1 b) 1 2 3 4 c) 2 1 3 4 d) 1 4 2 3 e) 3 1 2 4
Chem 2312-003 Midterm II F‘12
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11-12. (5 pts) Consider the following reaction:
BrMe
HH+ O
Me
HH
HOH Br+
ΔH (bonds broken) = 285 kJ/mol ΔH (bonds formed) = 381 kJ/mol
The following rate equation has been experimentally established for this transformation:
rate = k[HO–][CH3CH2Br]
The energy diagram for this transformation is shown below:
E
Reaction Coordinate
BrMe
HH+OH
OMe
HH
H Br+
11. Which of the following statements is not true?
a) ΔG, ΔH, ΔS, and Keq are thermodynamic factors.
b) The position of equilibrium will be significantly affected by an increase in temperature.
c) The reaction is exothermic.
d) The entropy of system is approximately zero.
e) The reaction is spontaneous.
12. Which of the following statements is not true?
a) Activation energy and temperature are kinetic factors.
b) The rate will be faster by an increase in temperature.
c) If the concentration of hydroxide is doubled, the rate will be doubled.
d) The transition state is close in structure to the products.
e) The reaction follows the second order kinetics.
Chem 2312-003 Midterm II F‘12
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13. (5 pts) Consider the following reaction.
MeHO H2SO4
H2Oproducts
Which of the following statements is not true?
a) A mixture of substitution and elimination products is produced.
b) The reaction is first order.
c) The reaction mechanism involves a carbocation rearrangement.
d) The reaction generates an intermediate.
e) One of the products is produced as a racemic mixture.
14. (5 pts) What is the major product of the following reaction?
a) b) c) d) e)
OH
Br
NaH
OH
Br
OHO
OH
H
Chem 2312-003 Midterm II F‘12
Page 6 of 7
15. (20 pts) Draw the Major product and a detailed arrow-pushing mechanism (step by step, draw all the intermediates) for the following reactions in the boxes provided. Specify the correct stereochemistry where appropriate.
BrMe NaOMe
MeOH
Chem 2312-003 Midterm II F‘12
Page 7 of 7
16. (20 pts) Draw the Major product and a detailed arrow-pushing mechanism (step by step, draw all the intermediates) for the following reactions in the boxes provided. Specify the correct stereochemistry where appropriate.
BrMe NaOMe
MeOH
***** End of Exam ***** You may pick up your exam on Thursday, November 8 (in class). Thank you!
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