CHEM 3311-100 Spring 2007
Exam 1
Professor R. Hoenigman
I pledge to uphold the CU Honor Code:
Signature______________________________________________
Name (printed)____________________________________________________
Last four digits of your student ID number_______________________________
Recitation TA_____________________________________________________
Recitation number, day, and time______________________________________
You have 1 hour and 30 minutes to complete this exam.
No model kits or calculators allowed.
Periodic table and scratch paper are attached.
DO NOT TURN THIS PAGE UNTIL INSTRUCTED TO DO SO.
Recitation Sections:
#
121
131
141
151
153
152
171
Day
Tuesday
Tuesday
Wednesday
Wednesday
Wednesday
Wednesday
Thursday
Time
8 am
1 pm
8 am
12 pm
12 pm
5 pm
12 pm
TA
Kelly
Kelly
Greg
Greg
Kelly
Kelly
Greg
SCORE:
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CHEM 3311, Spring 2007
Exam 1, page 1 of 7
1. (8 pts) Ammonia can act as either an acid or a base.
A. Draw the Lewis structure of ammonia.
B. What is the pKa of ammonia?
C. Fill in the equation below to relate the pKa of ammonia to its Ka.
Ka =
D. Draw the Lewis structure of the conjugate base of ammonia.
E. Draw the Lewis structure of the conjugate acid of ammonia.
2. (6 pts) Prozac®, shown below, is a widely prescribed antidepresent.
A. Label each atom indicated by a box as sp3, sp2, sp, or none of these.
B. Label each atom indicated by a circle as 1°, 2°, 3°, or 4°.
O
F3C
H
N
CHEM 3311, Spring 2007
Exam 1, page 2 of 7
3. (9 pts) Give the IUPAC name for each of the following compounds.
A.
H3C
CH2 CH(CH3 )2
B. (CH3CH2)2CHCH2CH(CH3)2
C.
CH2CH2CH(CH3)2
H3CH2C
H
H3C
CH2 CH2 CH2 CH3
CH3
4. (5 pts) Circle the compounds below that have a dipole moment.
HCN
H2O
BF3
CH3CH2COOH
CCl4
CH3Cl
CH2O
NCCH2CH2CN
cyclobutane
CHEM 3311, Spring 2007
Exam 1, page 3 of 7
5. (12 pts) State whether the following pairs of compounds are constitutional
isomers, stereoisomers, conformers, resonance structures, identical structures,
or have no relation. Place your answer in the box.
A.
and
B.
sec-butylcycloheptane
and
C.
and
D.
H
H3C
CH3
CH3
H3C
and
CH3
H3C
H
H3C
H
H
CH3
E.
and
Br
Br
F.
CH3
H
CH3
CH2CH3
H
CH3
H
H
and
H
CH3
H
CH2CH2CH3
CHEM 3311, Spring 2007
Exam 1, page 4 of 7
6. (18 pts) For each of the following pairs, circle the more stable compound or
ion. In the box, give a brief reason for your choice.
A.
1,1-dimethylcyclopentane
or
1-ethyl-3-methylcyclobutane
B.
cis-1-methyl-2-(1-methylethyl)cyclohexane
or
trans-1-methyl-2-(1-methylethyl)cyclohexane
C.
or
D.
H
H
H
H
H3C
H
or
H3C
H3C
CH(CH3)2
CH(CH3)2
CH3
H
E.
O
O
or
F.
O
O
or
N
N
CHEM 3311, Spring 2007
Exam 1, page 5 of 7
7. (9 pts) The following is a three-part question. Be sure to draw neat chair
cyclohexanes.
A. Draw the most stable conformer of cis-1-tert-butyl-4-methylcyclohexane.
B. Draw the most stable conformer of trans-1-tert-butyl-4-methylcyclohexane.
C. Which of the isomers (cis or trans) is more stable? Why?
8. (9 pts) Circle the more acidic compound in the following pairs. In the box, give
a brief reason for your choice.
A.
HC
or
CH
CH3 CH2OH
B.
(CH3 )3 NH
or
(CH3 )2OH
C.
CF3CH2 SH
or
CH3 CH2SH
CHEM 3311, Spring 2007
Exam 1, page 6 of 7
9. (4 pts) Circle the most acidic hydrogen in phenytoin, an anti-seizure drug.
O
H
N
HN
O
phenytoin
10. (10 pts) Carbonate (CO32-) is a very common polyatomic ion.
A. Draw all of the resonance structures of the carbonate ion. Be sure to show
any non-zero formal charges. Label each structure as a major or minor
resonance contributor.
B. Explain why all of the carbon–oxygen bonds in the carbonate ion have the
same bond length.
CHEM 3311, Spring 2007
Exam 1, page 7 of 7
11. (10 pts) Complete the following acid-base reactions. Show all non-zero
formal charges. If no reaction occurs write NR.
A. CH3CH2Li + H2O 
B. BF3 + CH3SCH3 
C. CH3COOH + CH3CONHNa 
D. C2H2 + NH2Na 
E. CH3OH + CH3SNa 