1. (12+6+6+5 = 29) Consider
the following ion. (You should know the
location of any lone pairs of electrons before answering the questions.)
+
CH2=CH–O=CH2
A B C D
a. Indicate the
hybridization at each atom (except hydrogen).
A ________
B ________
C ________
D ________
b. Draw a top view
that shows the correct geometry of this planar ion. All the bond angles should be shown. (Solid lines, only, are needed.)
c. Draw a side view of
the plane of the ion. Indicate the
geometry with wedges and hashed lines where needed. Place a p orbital (with top and bottom lobes
drawn) on each atom that has one. The p
orbitals should be vertical.
d. Draw one low energy
resonance form for the cation below. Add
the unshared electrons on this structure before drawing the resonance
form. Show the curved arrow(s) needed to
generate the new resonance form.
+
CH2=CH–O=CH2 ↔
2. (12) Draw two
isomers with the molecular formula, C4H6, both of which
have four different carbon atoms (i.e.
each isomer gives four 13C nmr signals).
3. (12) Draw the structure of
(2R,3Z)-2-fluoro-3-hexene.
4. (10) Draw the most
stable conformation of 1-chloro-2-methylpropane. Use a Newman projection that looks along the
C1-C2 bond.
5. (5) The heat of formation
of propyne is about + 45 kcal/mol.
Propadiene is
3 kcal/mole less stable than
propyne. What is the heat of formation
of propadiene?
__________ kcal/mol
6. (6) Why is ethyne
(HCΞCH) more acidic than methane?
7. (10) Using asterisks,
indicate all the stereogenic carbon centers in the penicillin below.
8. (5) What is the
relationship between compounds A and B?
A B
Are they A. identical
B. diastereomers Answer:______________________
C. enantiomers
D. meso compounds
9. a. (6) Draw a stereoisomer of
b. (5) What is the relationship between these two
stereoisomers?
Are they: A. identical
B. diastereomers Answer:______________________
C. enantiomers
D. meso
compounds
CHE 230 – Organic Chemistry
Exam 1,
Name
________________________________ Student ID Number ________________
Before you begin this exam: First:
You are allowed to have a simple model set at your seat. Please put away all other materials. Second:
Place your student identification on your desk.
A proctor will come around to check everyone’s ID. Third:
Read through the entire exam. Do not
waste time on problems that you can’t do if there are others that look
easy. Fourth: It is critically important that your answers be written in
a clear, unambiguous manner. Answers in which your intentions are unclear will
not receive credit. Fifth: Read the instructions for each problem. You will have until
Problem Points Score
1a. 12 _____
1b. 6 _____
1c. 6 _____
1d. 5 _____
2. 12 _____
3. 12 _____
4. 10 _____
5. 5 _____
6. 6 _____
7. 10 _____
8. 5 _____
9a. 6 _____
9b. 5 _____
Total 100 _______