Transcript Exam 10 & 11 Practice

Chemistry 107
Exam 10 & 11
Good Luck!
1. PCl3 is an industrial chemical used in
many herbicides and insecticides. What is
the molecular shape of PCl3?
a) Bent
b) Tetrahedral
c) Trigonal pyramidal
d) T-shaped
e) Trigonal planar
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2. What is the approximate angle of
the O─C─O bond in the citric acid
molecule below?
O
a)
b)
c)
d)
e)
120 º
109.5 º
< 120 º
< 109.5 º
> 120 º
O
OH
OH
O
HO
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HO
3. What is the hybridization of the central
atom in XeF2?
a) sp
b) sp2
c) sp3
d) sp3d
e) sp3d2
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4. Which of the following molecules is
the most polar molecule?
Br
Te
Cl
Br
Te
Br
Br
a)
F
Cl
Te
Cl
Cl
b)
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Cl
F
Te
F
Br
Br
Te
Br
F
Cl
c)
d)
Cl
Cl
Br
e)
5. Which orbitals overlap to form the sigma
bond between the sulfur and fluorine atoms
in the molecule SF4?
a)
b)
c)
d)
e)
sp3d hybrid of S and 2p of F
sp3 hybrid of S and 2p of F
sp2 hybrid of S and 3p of F
sp3d2 hybrid of S and 2p of F
sp3d hybrid of S and 3p of F
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6. When determining the electron geometry:
a) only electrons on the central atom are
considered.
b) the electrons on all the atoms are considered.
c) electrons on outer atoms affect the overall
geometry.
d) electrons in lone pairs are considered only
when the molecule is polar.
e) All of the above are true.
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7. Which of the following hybridization
schemes allows the formation of at least one
 bond?
a)
b)
c)
d)
e)
sp3
sp2
sp3d2
All of the above allow for a  bond.
None of the above allow for a  bond.
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8. How many  electrons are found in
the amino acid aspartic acid?
a) 2
b) 4
c) 17
d) 34
e) All of the valence
electrons are
considered  electrons.
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9. How many lone pairs are found
in a caffeine molecule?
a) 0
b) 4
c) 6
d) 8
e) 12
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10. Determine the electron geometry of the
labeled oxygen in aspartic acid.
a)
b)
c)
d)
e)
Linear
Tetrahedral
Trigonal pyramidal
Bent
Trigonal planar
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11. List the following molecules in order
of increasing boiling point:
O
dimethyl ether
O
H
n-propanol
O
diethyl ether
a) n-propanol < dimethyl ether < diethyl ether
b) diethyl ether < dimethyl ether < n-propanol
c) dimethyl ether < diethyl ether < n-propanol
d) dimethyl ether < n-propanol < diethyl ether
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12. Zinc sulfide crystallizes in the unit cell shown below.
How many formula units are found within this unit cell? In
the figure, Zn is represented by gold spheres.
a)
b)
c)
d)
e)
1
2
3
4
None of the
above
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13. The vapor pressure of nitrogen is tabulated as a
function of temperature below. Calculate the heat of
vaporization of nitrogen.
a) 5.92 kJ/mol
b) 9.90 x 10–2 J/mol
c) 64.2 J/mol
d) 1.75 x 10–5 J/mol
e) 5.85 x 10–2 kJ/mol
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Temperature
(K)
65
70
75
80
85
Pressure
(torr)
130.5
289.5
570.8
1028
1718
14. Which type of intermolecular force is the strongest?
a)
b)
c)
d)
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15. In each figure, the dashed line represents the threshold
kinetic energy required to vaporize the liquid. Both
substances are at the same temperature.
Substance B
Fraction of Molecules
Fraction of Molecules
Substance A
Kinetic Energy
Kinetic Energy
Which has the strongest intermolecular forces?
a) Substance A
c) Both are the same
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b) Substance B
d) Can’t tell
16. In each figure, the dashed line represents the threshold
kinetic energy required to vaporize the liquid. Both
substances are at the same temperature.
Substance B
Fraction of Molecules
Fraction of Molecules
Substance A
Kinetic Energy
Kinetic Energy
Which has an exothermic ΔHvaporization?
a) Substance A
c) Both are the same
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b) Substance B
d) Neither
17. Which of the following is the most viscous?
a)
b)
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c)
d)
e)
18. Which of the following is cubic closest packed?
a)
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b)
c)
19. How much energy is required to vaporize
32.9 g of ethanol at its boiling point, if its
Hvap is 40.5 kJ/ mol.
a) 28.9 kJ
b) 3.83 kJ
c) 6.30 kJ
d) 17.6 kJ
e) 7.60 kJ
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The Answers
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1. c
2. e
3. d
4. c
5. a
6. a
7. b
8. b
9. d
10. b
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11. c
12. d
13. a
14. d
15. a
16. d
17. c
18. d
19. a