Chem 14B, Fall 2001
EXAM II, Page 5
_______________________
Please Print Last Name
D.
EXPLORE THIS STRUCTURE. Answer each question; all are related to the
1. (17
questions
to the
of (not
scopolamine.
structure
of points)Answer
scopolamine. the
Small
lettersrelated
refer to
the structure
questions
all questionsSome
have letters on the
drawing).
questions refer to letters on the drawing.
CH3
N
b1
SCOPOLAMINE
(treatment of
motion sickness)
O
e
OH
a
O
O
b2
a.(4) Using the notation (Atom orbital - Atom orbital), describe all FOUR bonds
to the the
carbon
labelled
"a".orbital - Atom orbital), describe all FOUR bonds to the carbon
a.(4) Using
notation
(Atom
3
3
(Csp
–
Osp
)
labelled "a".
(Csp3 – Csp3)
(Csp3 – Hs)
(Csp3 – Hs)
b.(4) Name each functional group: b1___________
b2____________
b.(2) Name each functional group: b1__amine
b2_ester__
c.(2) Is the alcohol primary, secondary, or tertiary? _____________________
c.(2) What is the O – C – C bond angle at “a”? Use >,<,= notation as
appropriate.
d.(2) Circle which bond is shorter: (C sp3 - Osp3 ) or (C sp2 - Osp3 ) .
________> 109.5°____________
e.(2) d.(1)
WhatCircle
is thewhich
geometry
the O(C
atsp3
"e"?
______________
bondaround
is shorter:
- Osp3
) or (Csp2 - Osp3) .
f.(2)
e.(1) What is the geometry around the O at "e"? __tetrahedral_____
On the drawing, circle and label the "Ph".
f. (1) What is the name of the functional group at “e”?___epoxide_____
g.(4) If the -CH2OH substituent is replaced with -OCH3, would the resulting structure be an
g.(1)
the -CH2OH substituent
is replaced with -OCH3, would the resulting
"isomer"
of Ifscopolarmine?Yes/No
______
structure be (circle one): an isomer of scopolamine or an unrelated
If so, what kind of isomer? ______________
molecule
h. (1) Which bond is more polar (circle one): C – N or C – O?
i. (1) How many sp2 hybridized atoms are in scopolamine?______8________
j. (1) How many lone pairs are in scopolamine?________9______
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d. 1,3-Diaxial interactions in cyclohexane are a specific example of ____________strain.
D.(4) Resonance: draw two more resonance structures (there are actually 5 total)
k. (2) What is the molecular formula of scopolamine?____C17H21O4N___
2. (3 points) Compare each structure to the boxed one and determine
whether
each is a resonance structure.
E. (6) Resonance: compare each structure to the boxed one and determine whether each is a
resonance structure.
O
O
O
O
Resonance
structure? YES/NO
YES
YES
NO
3. (7 points) Draw two more resonance structures for the structure shown
below.
(a)
O
O
O
(b) (4) Draw the resonance hybrid for the structures drawn in part (a).
δ+
O
δ+
δ+
4. (7 points) (a) Use VSEPR theory to draw the 3-dimensional structure
(showing ALL dashes and wedges) of diethyl ether, CH3CH2OCH2CH3. Draw
all dipole arrows for all polar bonds.
H H
H
H
H
C
C
H
O
H
C
H
C
H
H
(b) The C-O-C bond angle is circle one (>, <, = ) ____>
109.5°______________.
2
5. (12 points) The following questions refer to isomers of C3H6O. There are 9
isomers in which all of the atoms have no formal charges.
(a) Three of the nine isomers of C3H6O have Lewis structures with NO
sp2 hybridized atoms. Draw one of them in the box below.
O
or
OH
or
O
(b) Draw an isomer of C3H6O with an sp2 hybridized oxygen atom.
or
O
O
(c) Draw an isomer of C3H6O that you would predict to have a higher
boiling point than the structure you drew for part (b).
OH
or
OH
+ other possible answers
(d) WHY does stucture “c” have a higher boiling point than “b”?
Hydrogen bonding interactions in (c) are stronger than the C-O dipoledipole interactions in (b).
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