Seat Assignment: _________________
Elementary Organic Chemistry
Chem 209
Exam I
October 1, 2009
Name (print): _____________________
Name (sign): _____________________
Student Number: __________________
Multiple Choice Answers (one letter per question, 3 points each)
5. _____________
11. _____________
6. _____________
12. _____________
7. _____________
13. _____________
8. _____________
14. _____________
9. _____________
15. _____________
10. _____________ 16. _____________
subtotal: _______________
Written Answer Questions (overpage, 4 points each): subtotal: __________________
Total: ________________
Please note: pencil is recommended!
1
Written Answer Questions (4 points each)
1.
Draw, on the template, the structure of 2R,3R-dichloropentane. Use dashes and
wedges to indicate absolute stereochemistry.
2.
Draw the major product of the following reaction.
3.
Draw the energy diagram for the reaction shown in question 2, above. Consider
only the steps involving carbon atoms.
4.
Draw in the box, by using a Newman projection, the highest energy (least stable)
conformation of the C2–C3 bond of butane (CH3-CH2-CH2-CH3). Is it staggered
or eclipsed?
2
Multiple Choice Questions (3 points each)
5.
Give the major product.
6.
Given the energy diagram below for the reaction of Br2/AlBr3 with benzene,
identify the total energy change ∆E (released) for the reaction.
A.
B.
C.
D.
E.
a
b
c
d
e
3
7.
For the reaction in question 6 above, how many steps are there, and how many
intermediates?
A.
B.
C.
D.
E.
8.
What is the reason normally given for the observed order of stability of
carbocations, 3° > 2° > 1° ?
A.
B.
C.
D.
E.
9.
1 step, 1 intermediate
2 steps, no intermediates
2 steps, 1 intermediate
2 steps, 2 intermediates
3 steps, 2 intermediates
alkyl groups are electron-releasing relative to H
alkyl groups are electron-withdrawing relative to H
alkyl groups destabilize a positive charge by resonance
alkyl groups are more sterically hindered (larger) than H
alkyl groups can exist in more conformations than H
Which of the following is the most stable cyclohexadienyl cation?
4
10.
Under acid catalysis, acetic acid reacts with alkenes. Draw the major product.
Hint: this is a Markovnikov addition.
11.
All of the carbons of which molecule, in its most stable conformation, lie in a
single plane?
A.
B.
C.
D.
E.
cis-1,2-dichlorocyclopropane
cyclobutane
cyclopentane
cyclohexane
1,1-dimethylcyclopropane
5
12.
What is the formal charge on S?
A.
B.
C.
D.
E.
13.
+2
+1
0
-1
-2
What is the molecular formula for the line structure shown below?
A.
B.
C.
D.
E.
14.
C12H10
C12H15
C11H15
C11H10
C12H16
Arrange the following liquids in order of most-to-least soluble in hexane:
I: n-decane
A.
B.
C.
D.
E.
15.
II: water
III: n-butanol
I > II > III
I > III > II
II > III > I
III > I > II
III > II > I
Which of the following is achiral?
A.
B.
C.
D.
E.
(S)-lactic acid
cis-1,2-dichlorocyclohexane
1-bromo-1-chloroethane
1-bromo-2-chloropropane
cis-1-bromo-2-chlorocyclohexane
6
16.
Which of the following has the smallest heat of hydrogenation per C=C bond (=
total ∆Hhydrog / # of C=C’s)? Hint: this is a measure of C=C stability.
A.
B.
C.
D.
E.
1-methylcyclohexene
1-methyl-1,3-cyclohexadiene
2-methyl-1,3-hexadiene
2-methyl-2-hexene
toluene
7
8