Name: _______________________________
Circle Class Section : 9 am or 10 am
CH241 (Fall, 2013)
Hour Exam #1
Monday, September 30, 2013
Duration: 60 minutes (5:30 to 6:30 pm)
Instructions: (a) Check to make sure that this exam has 4 pages including this page.
(b) Write your name on the top of this page and circle your section.
(c) Write your answers in the space provided.
(d) This is a closed book exam.
(e) You may use the back of any page on this exam for scratch work.
Points:
Question 1
Question 2
Question 3
Question 4
_____
_____
_____
_____
out of 36 points
out of 32 points
out of 14 points
out of 18 points
Total Score
_____ out of 100 points
Good Luck!
[1]
(a) (4 pts) Provide the correct IUPAC name for the following compound.
Cl
H
H3C
H
CH3
CH2CH3
(b) (4 pts) Which one of the following would have a half-filled antibonding orbital?
H2
H2+
He2
He2+
(c) (4 pts) Draw the correct structure for 2,7-dibromo-4-isopropyloctane.
(d) (4 pts) Rank the following alkenes according to their stability (1 being most stable
and 4 least stable)
(e) (4 pts) Provide the systematic name for ANY ONE of the compounds in part (d). Be
sure to indicate which structure you named.
(f) (4 pts) Circle the combination of orbitals that will give the most stable sigma bond.
sp-sp3
sp2-sp3
sp-sp
sp3-sp3
(g) (6 pts) Using the Cahn-Ingold-Prelog convention, assign priorities and correctly
designate the following compound as the E or Z isomer. Please show your work.
O
H
HO
(h) (6 pts) Looking down the C1-C2 bond, draw Newman projections for the best and
worst conformations of 1-bromopropane.
2
[2]
(a) (4 pts) Determine the degree of unsaturation in diazomethane, H2CN2. Show your
calculation.
(b) (10 pts) Write a reasonable Lewis structure for diazomethane given the skeleton
below. Your structure should comply with the octet rule for non-hydrogen atoms (and
duet for hydrogens). Be sure to assign correct formal charges to ALL atoms. Show your
calculation of formal charge for ANY ONE atom.
H
C
N
N
H
(c) (4 pts) Write another Lewis structure, complete with formal charges, for a reasonable
resonance form of your answer to part (b). This structure, too, should satisfy the
octet/duet rule.
(d) (4 pts) Using arrow formalism, show how one of the resonance structures you drew
above might be converted into the other.
(e) (10 pts) Provide a correct Lewis structure for a different molecule that is an isomer of
diazomethane. Clearly identify the hybridization of carbon and both nitrogens in this
structure.
3
[3]
Consider the molecule below and answer the questions that follow.
N
N
O
(a) (4 pts) Circle one example of each of the following: a 1°, 2°, 3°, and 4° carbon.
(b) (3 pts) Circle a methyl, methylene, and methine group.
(c) (2 pts) Which features of the molecule accounts for its four degrees of unsaturation?
(d) (5 pts) One of the nitrogens in the molecule is sp3 hybridized and the other is sp2
hybridized. Correctly identify these nitrogens and, using proper structures, explain
why the hybridization states are different.
[4]
Provide structures and IUPAC names for the following.
(a) (6 pts) A molecule of the formula C4H6F2 that has no net dipole.
(b) (6 pts) A molecule of the formula C3H4Cl2 that may be designated using cis/trans but
not E/Z notation.
(c) (6 pts) A molecule of the formula C6H12 that has only two kinds of carbons.
4