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Exam 1
Name __________________________
CHEM 210
1.
(6 pts) Give each non-hydrogen atom the proper formal charge, even if zero; all electrons are shown.
a.
2.
3.
4.
b.
c.
(9 pts) Draw one valid Lewis structure for each compound. Assign formal charges to atoms if necessary.
a. nitromethane, CH3NO2
b. ozone, O3
c. hydrazine, N2H4
(16 pts) Consider the following steroid used in the treatment of prostate cancer:
a. What is the hybridization of atom a? ______ e? ______ h? ______
b.
What is the bond length of e-f? ______ k-m? ______ b-j? ______
c.
How many hydrogens are on atom i? ______ g? ______
d.
How many lone pairs on atom h? ______ k? ______ a? ______
e.
What is the geometry of atom a? __________________________
f.
What orbital does the lone pair on j reside? ______
g.
What orbitals are used to bond a-b? ______________________ __ _
h.
What bonds make up c-d? _______________________
(12 pts) Name the functional groups in the following pharmaceuticals:
a.
b.
Fluoxetine (Prozac ®)
5.
d.
Aspirin
Which two atomic orbitals overlap to form the MOs of σ symmetry that correspond to the C-C bond in ethylene?
a. 2s and 2p
d. sp3 and sp3
b. 2p and sp2
e. 2p and 2p
c. sp2 and sp2
6.
Recall that ethyne is HC
a. H2s and C2p
b. H1s and C2p
c. H1s and Csp2
CH. Which two orbitals share electrons in one of ethylenes covalent C—H bonds?
d. H1s and Csp2
e. H1s and Csp
7.
An alkene contains a double bond. Why is the C C of an alkene rigid and unable to freely rotate?
a. The C C bond is very strong, and it is impossible to break it.
b. The σ bond gets blocked by the hydrogen atoms.
c. The sp2 hybrid orbitals of carbon take up too much room.
d. The π electrons are delocalized through the σ bonds.
e. The 2p orbitals of the π bond overlap above and below the C=C plane to restrict rotation.
8.
Which characteristics describe the bonding MO for the weakest individual covalent bond in ethene, C 2H4?
I. The MO possesses π symmetry.
II. The MO possesses σ symmetry.
III. The MO can be called the HOMO.
IV. The MO can be called the LUMO.
V. The MO contains two electrons of opposing spin.
a. All of the choices
d. I and V
b. II, III, and V
e. I, III, and V
c. II and V
9.
One of the following statements about the relationship of % s character to organic structure is false. Identify which
statement is false.
a. The % s character and effective electronegativity are directly proportional to one another.
b. An sp3 orbital has greater % s character than an sp2 orbital.
c. Two orbitals with high % s character will form a stronger bond.
d. A 2s orbital has greater s character than any of the hybrid orbitals.
e. An orbital with greater % s character is smaller and more compact.
10. (6 pts) Rank the following analgesics in order of increasing water solubility (1 – least soluble, 4 – most soluble):
Which drug do you think gets into the bloodstream the fastest? __________________
Which drug do you think has the longest lifetime in the tissues (think carbon chains in fatty acids)?
____________
11. (2 pts) Assuming roughly equivalent molecular weights, which of the following would have the highest melting point?
A) amine
B) sodium salt of a carboxylic acid
C) alcohol
D) ether
E) alkyl chloride
12. (3 pts) Rank the following compounds in order of increasing boiling point (1-lowest to 4-highest):
13. (8 pts) Draw all contributing resonance structures for each molecule:
a.
b.
14. (6 pts) Draw four isomers of C5H10O that are both alkene and ether. One pair of compounds must be cis-trans isomers;
label each as such.
15. (6 pts) Chemistry isn’t just for chemists. Methanimine is a compound found in the upper atmosphere
of the Saturnian moon Titan. Compounds of this type may be responsible for creating the building
blocks of life. Sketch the orbital model (‘balloon animal’) for methanimine below. Be sure to label the
bonds between within the structure as  or , label the orbitals and indicate all bond angles.
16. (6 pts) Why do polar aprotic solvents solvate cations more strongly than anions? Using sodium chloride as
the representative ionic compound, diagram the intermolecular interactions with tetrahydrofuran (THF ,
shown).
SCORE ____________/125
Approximate Course Grade: A
A-
B+
B
B-
C+
C
D
F
KEY
CHEM 210
1.
(6 pts) Give each non-hydrogen atom the proper formal charge, even if zero; all electrons are shown.
a.
2.
3.
b.
c.
d.
(9 pts) Draw one valid Lewis structure for each compound. Assign formal charges to atoms if necessary.
a. nitromethane, CH3NO2
b. ozone, O3
c. hydrazine, N2H4
(16 pts) Consider the following steroid used in the treatment of prostate cancer:
i. What is the hybridization of atom a? sp2 e? sp h? sp3
j.
What is the bond length of e-f? 1.3 Å k-m? 1.0 Å b-j? 1.5 Å
k.
How many hydrogens are on atom i? 1 g? 2
l.
How many lone pairs on atom h? 3 k? 2 a? 2
m. What is the geometry of atom a? trigonal planar
4.
n.
What orbital does the lone pair on j reside? sp3
o.
What orbitals are used to bond a-b? 2sp2 and 2p
p.
What bonds make up c-d?  and 
(12 pts) Name the functional groups in the following pharmaceuticals:
a.
b.
Fluoxetine (Prozac ®)
5.
Aspirin
Which two atomic orbitals overlap to form the MOs of σ symmetry that correspond to the C-C bond in ethylene?
a. 2s and 2p
d. sp3 and sp3
2
b. 2p and sp
e. 2p and 2p
c. sp2 and sp2
6.
Recall that ethyne is HC
a. H2s and C2p
b. H1s and C2p
c. H1s and Csp2
CH. Which two orbitals share electrons in one of ethylenes covalent C—H bonds?
d. H1s and Csp2
e. H1s and Csp
7.
An alkene contains a double bond. Why is the C C of an alkene rigid and unable to freely rotate?
a. The C C bond is very strong, and it is impossible to break it.
b. The σ bond gets blocked by the hydrogen atoms.
c. The sp2 hybrid orbitals of carbon take up too much room.
d. The π electrons are delocalized through the σ bonds.
e. The 2p orbitals of the π bond overlap above and below the C=C plane to restrict
rotation.
8.
Which characteristics describe the bonding MO for the weakest individual covalent bond in ethene, C 2H4?
I. The MO possesses π symmetry.
II. The MO possesses σ symmetry.
III. The MO can be called the HOMO.
IV. The MO can be called the LUMO.
V. The MO contains two electrons of opposing spin.
a. All of the choices
d. I and V
b. II, III, and V
e. I, III, and V
c. II and V
9.
One of the following statements about the relationship of % s character to organic structure is false. Identify which
statement is false.
a. The % s character and effective electronegativity are directly proportional to one another.
b. An sp3 orbital has greater % s character than an sp2 orbital.
c. Two orbitals with high % s character will form a stronger bond.
d. A 2s orbital has greater s character than any of the hybrid orbitals.
e. An orbital with greater % s character is smaller and more compact.
10. (6 pts) Rank the following analgesics in order of increasing water solubility (1 – least soluble, 4 – most soluble):
Which drug do you think gets into the bloodstream the fastest? Aspirin
Which drug do you think has the longest lifetime in the tissues (think carbon chains in fatty acids)? Ibuprofen
11. (2 pts) Assuming roughly equivalent molecular weights, which of the following would have the highest melting point?
A) amine
B) sodium salt of a carboxylic acid
C) alcohol
D) ether
E) alkyl chloride
12. (3 pts) Rank the following compounds in order of increasing boiling point (1-lowest to 4-highest):
13. (8 pts) Draw all contributing resonance structures for each molecule:
a.
b.
14. (6 pts) Draw four isomers of C5H10O that are both alkene and ether. One pair of compounds must be cis-trans isomers;
label each as such.
15. (6 pts) Chemistry isn’t just for chemists. Methanimine is a compound found in the upper atmosphere
of the Saturnian moon Titan. Compounds of this type may be responsible for creating the building
blocks of life. Sketch the orbital model (‘balloon animal’) for methanimine below. Be sure to label the
bonds between within the structure as  or , label the orbitals and indicate all bond angles.
16. (6 pts) Why do polar aprotic solvents solvate cations more strongly than anions? Using sodium chloride as the
representative ionic compound, diagram the intermolecular interactions with tetrahydrofuran (THF, shown).
SCORE ____________/125
Approximate Course Grade: A
A-
B+
B
B-
C+
C
D
F