Chemistry 321
50-Minute Examination #1
Friday, February 14, 2003
VERSION A.
Write your answers in the space provided on the Answer Sheet provided. Keep this examination;
turn in only the Answer Sheet.
1. Draw the Lewis electron dot structure of formamidine, CH4N2. The carbon atom is bonded to
one hydrogen atom and the two nitrogen atoms. There is no nitrogen-nitrogen bond in
formamidine. [10 points]
2. Draw an acceptable Lewis dot structure for acetone, CH3COCH3. [8 points]
3. What is the hybridization of the indicated atoms on the structure
at right? [10 points]
c
b
N
C
d e
4. What is the molecular formula of the molecule at right? [6 points]
5. What type of molecular orbital is the lowest energy empty
molecular orbital in the compound at right? [4 points]
O
a
CHO
6. Acetophenone, C6H5COCH3 has a pKa of 26.5; ammonia has a pKa of 33.5.
(a) What will be the approximate equilibrium constant for the formation of acetophenone anion,
C6H5COCH2—, by the reaction between acetophenone and potassium amide (KNH2)? [6 points]
(b) Is amide ion a sufficiently strong base to convert most of the acetophenone to its conjugate
base? [2 points]
7. Name the following organic compounds. [18 points]
Br
Br
OH
(a)
(b)
(c)
Br
8. The name, 2,6-diethyl-4-methylheptane, is not correct, but it can be used to draw the structure
of the molecule. Draw the molecule and give its correct name. [8 points]
9. The conjugate acid of thiourea, CH5N2S+, has a structure in which a central carbon is bonded
to the two nitrogen atoms and the sulfur atom. There is one hydrogen-sulfur and no hydrogencarbon bond. Each nitrogen is bonded to two hydrogen atoms. Draw all the different possible
resonance contributors can be drawn for this cation. [12 points]
d
CH 3
N
10. There are seven heteroatoms in the molecule at right. a
What is the formal charge on each? [14 points]
b
O
c
11. How many lone pairs are on the boron atom in B(CH3)3? [2 points]
N
O
N
e
O
C
O
f
g
CHEMISTRY 321
50-MINUTE EXAMINATION #1 — Version A
FRIDAY, FEBRUARY 14, 2003
NAME (Print!):
1.
2.
H
N
H C
N H
H
3. (a) sp3 (b)
4.
6. (a)
O
H
C
H
C
C
H
H
H
H
sp
(c)
sp
C12H17NO2
107
7 (a)
4,8-diethyl-4,5-dimethylundecane
7 (b)
5,6,6-trimethyl-1-octanol
7 (c)
5,6,6-tribromo-2-methyl-2-octene
8 (a)
8 (b)
3,5,7-trimethylnonane
(d)
5.
sp2
(e)

(b)
yes
sp2
9.
H
10.
11.
N
H
S
C
H
N
H
H
H
N
H
S
C
H
N
H
H
H
N
H
(a)
0
(b)
+1
(c)
-1
(e)
0
(f)
0
(g)
-1
0
S
C
H
N
H
H
(d)
+1