Name: _________________________________
CHEM 331. Practice Midterm 1
Fall 2014
Prof Donald Watson
Please write your answers clearly in the boxes provided. If your answer is illegible or
outside the box, it will not be graded. You may use the back of test pages for scratch
work.
You may use molecular models.
Use of calculators, cell phones, headphones, or any other electronic device during this
exam is prohibited.
No notes or books may be used during this exam.
You may raise your hand to ask a question if you are not sure what is being asked of
you.
There are 10 pages in this exam. Please check that your test has 10 pages before you
begin. The last 3 pages are blank and may be used as scratch paper.
Question
Points
1
_____ /15
2
_____ /30
3
_____ /25
4
_____ /20
5
_____ /10
Total
____
/100
1
Name: _________________________________
1. (10 points) Please assign formal charge to any atoms that require it. Assume all
atoms are included.
H
Me
H
H 2C
Me
Me
N
H
H 2C
O
C
H2
H 2C
CH2
H
H
N
CH2
H 2C
H H
O
Me
N
C
N
O
F
F
S
H
Cl
2
Name: _________________________________
2. (30 points) Within each box, provide all significant resonance contributors for each
molecule. Please indicate which are major and which are minor contributors. If no other
significant resonance structures exist, state so.
Me
O
N
Me
3
Name: _________________________________
3a. (5 points) On the structure below, please indicate the hybridization of all nonhydrogen atoms in ketene.
O
C
Me
Me
ketene
3b. (10 points) In the space below, please sketch the bonding π-orbitals involved in
ketene. Please be sure to clearly indicated geometric relationships, as needed.
4
Name: _________________________________
3c. (10 points) In the space below, please draw the molecular orbital diagram of the
C=O double bond. Clearly label all AO's and MO's.
5
Name: _________________________________
4. (20 points) Shown below are two Newman projections from an isomer of 3-bromo,-3methyl,-4-amino,-4-methyl,-6-hydroxy,-7-hydroxyoctane. On the structure below, please
provide complete the structure, including stereochemistry. Once done, please assign
each the stereochemistry of each stereocenter.
Br
OH
C5
H
C5
NH 2
Me
H
Me
Et
OH
view down C7 to C6 bond
Me
view down C 3 to C 4 bond
Me
Me
6
Name: _________________________________
5. (10 points) Are the following pairs of molecules enantiomers, diastereomers,
structural isomers, or identical?
Me
Me
Me
Me
a)
Me
Me
Me
b)
Me
OH
Me
OH Me
Me
Me
OH
OH
H
H
H
O
c)
H
Me
O
Me
Me
Me
O
O
HO
OH
d)
Me
Me
Me
Me
Me
HO
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
O
O
HO
e)
OH
OH
Me
Me
Me
Me
Me
Me
HO
OH
7
Name: _________________________________
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8
Name: _________________________________
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9
Name: _________________________________
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10