Homework Set #2
Chemistry 1315
Spring 2004
_____Answer Key____________
Name
Handed Out:
Due:
1-15-04
1-22-04 at 9:30 am in class
Late Policy:
One day late (1-23-04 10am):
Two days later (1-24-04 10 am):
After 10 am 1-24-04:
50% off
75% off
no credit
You may work in groups up to 3 students. However, each student must make contributions to the answers.
Questions
1
2
3
4
5
6
7
8
Total:
Points Possible
10
10
10
10
10
15
20
15
100
Score
Question #1 (10 pts.)
Draw the structures for the following compounds: (2 points each)
a) 3-Ethyl, 4-methyl-1,5-hexadiene
b) 4-Methyl-1-cyclooctene
c) 4-n-propylheptane
d) 1-Ethylcyclohexene
e) 3,6,10-trimethyl-2,4,6,8-dodecene
Question #2 (10 pts.)
Draw the most stable chair form of each of the following and explain why it is stable (use the cyclohexane
template provided) : (1 point labeling, 1 point for reason)
a) trans-1,2-dimethylcyclohexane
CH3
b) cis-1-ethyl-2-methylcyclohexane
CH2CH3
CH3
CH3
Both Equatorial
Larger group equatorial
c) trans-1,4-dimethylcyclohexane
H 3C
CH3
Both equatorial
d) cis-1-ethyl-3-methylcyclohexane
H3C
CH2CH3
Both equatorial
d) trans-, trans-1,2,3-trimethylcyclohexane
H3C
CH3
All equatorial
CH3
Question #3 (10 pts.)
Draw the following structure in its most and least stable CHAIR conformation, using orbital shapes, explain
why the stable conformation is so. (5 pt for structure, 5 pt for reason (must include orbitals in answer).)
H3C
CH2
CH3
Orbital interacting with CH3
CH3
H3C
No orbital interaction
H3C
CH3
Question #4 (10 pts.)
Name the following compounds using IUPAC nomenclature: (2 points each)
a)
1-isopropyl-3-methyl-cyclohexane
b)
3,4-diethyl-2,5-dimethylheptane
c)
t-butylcyclopentane
d)
5-ethyl-2,2,7,7-tetramethyldecane
e)
(2-ethylbutyl)cyclohexane
Question #5 (10 pts)
Determine whether the following are the same compound (10 pts). (2 points each)
H
H3C
H
H
a)
H
H
CH3
H
CH3
H
CH3
H
H3C
H3C
H
b)
H3C
H3CH2C
c)
H3C
H3C
d)
H
H3C
e)
H
H
CH3
H
CH3
H3C
H
CH3
CH3
CH3
CH3
CH2CH3
H3C
CH3
H3C
H
H
H
H
H3C
CH3
CH2CH3
H
CH3
CH2CH3
yes
H
yes
CH2CH3
CH2CH3
H
CH3
yes
H
CH3
CH3
H
H3CH2C
yes
CH3
H
CH2CH3
CH3
no
Question #6 (15 pts.)
For the compound below:
a) Identify the polar bonds using δ+ and δ-
(2 points)
b) If you add a generic base (R-), where would it attach (show curved arrow mechanism) (10 points)
c) Now you add an acid (H+), show where it would attack using curved arrows (3 points)
O
a)
H3C
d-
C
CH3
d+
O-
O
H3C C CH3
+ R-
H3C C CH3
R
H+
+
OH
H3C
R
CH3
Question #7 (20 pts.)
Draw 10 isomeric alkenes and give the IUPAC names for C7H12. (1 point structure, 1 point name, you only need
10, there may be additional structures)
1,3-Heptadiene
1,4-Heptadiene
2,4-Heptadiene
2,5-Heptadiene
4-Methyl-cyclohexene
Cycloheptene
1,5-Heptadiene
1,6-Heptadiene
1-Methyl-cyclohexene
Vinyl-cyclopentane
3-Methyl-cyclohexene
3,5-Dimethyl-cyclopentene
4,4-Dimethyl-cyclopentene
1,3-Dimethyl-cyclopentene
1,2-Dimethyl-cyclopentene 1,4-Dimethyl-cyclopentene
3,3-Dimethyl-cyclopentene
1,2,3-Trimethyl-cyclobutene
1-Propyl-cyclobutene
1-Ethyl-cyclopentene
3-Ethyl-cyclopentene
1-Ethyl-2-methyl-cyclobutene
1-Isopropyl-cyclobutene
4-Ethyl-cyclopentene
1-Ethyl-4-methyl-cyclobutene
1-Ethyl-3-methyl-cyclobutene
Question #8 (15 pts.)
Identify the Bronsted acid, base, conjugate acid, and conjugate base in the reactions below. Draw the curved
arrow mechanism for each reaction. (1 point for Acid/Base label, 1 point each arrow)
+ -OH
OH
O-
O
O
Acid
Base
H
+
H
Base
+ H2O
H
H
O
Conj. Base
H
H
+
H
Acid
H
Conj. Acid
H
Conj. Acid
(Acid)
H
O
H
Conj. Base
(Base)
OH
H
H
+ H+
Conj. Base Conj.Acid