CHEMISTRY 110 EXAM 2
Feb 25, 2013
FORM A
--------------------------------------------------------------------------------1. How many valence electrons and lone pairs are in the structure
of the ammonium ion?
A. B. C. D. E. # valence electrons 8 10 8 10 12 # lone pairs 0 1 1 2 3 --------------------------------------------------------------------------------2. Which of the following best represents the molecular structure
of COS?
A. I
B. II
C. III
D. II and III are equally good representations.
E. I and II are equally good representations.
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--------------------------------------------------------------------------------3. What is the arrangement of electron domains about the
central atom in formaldehyde, H2CO?
A. Tetrahedral
B. Trigonal planar
C. Square planar
D. Trigonal bipyramidal
E. Linear
--------------------------------------------------------------------------------4. Which of these molecules is/are non-polar?
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
I
II
III
IV
A. I only
B. II only
C. IV only
D. I and IV
E. II and III
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--------------------------------------------------------------------------------5. What functional groups are present in the molecule below:
A. alcohol, amine, aldehyde
B. amine, aldehyde, ketone
C. amine, ketone, carboxylic acid
D. alcohol, ketone, carboxylic acid
E. ketone, carboxylic acid, ester
--------------------------------------------------------------------------------6. What is the correct molecular formula for the following molecule:
A. C4H8O2
B. C4H10O2
C. C5H8O2
D. C5H10O2
E. None of the answers listed here are correct
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--------------------------------------------------------------------------------7. Which one of the following organic molecules would not have
dipole-dipole interactions as one of its intermolecular forces?
O
OH
NH2
A.
B.
C.
O
O
OH
D.
E.
--------------------------------------------------------------------------------8. Which one of the following molecules is nonpolar?
A. NH3
B. OF2
C. CH3Cl
D. H2O
E. BeCl2
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--------------------------------------------------------------------------------9. What is the hybridization of As in the AsF4– ion?
A. sp
B. sp2
C. sp3
D. sp3d
E. sp3d2
--------------------------------------------------------------------------------10. The structure of citric acid is given below. What is the
hybridization of the two labeled carbons? ?
A. 1 sp 2 sp2 B. sp2 sp3 C. sp3 sp2 D. sp3 sp E. sp2 sp2 ---------------------------------------------------------------------------------
--------------------------------------------------------------------------------11. Arrange the following substances in order of increasing
boiling point.
i.
ii.
iii.
A. i < ii < iii
B. i < iii < ii
C. ii < iii < i
D. iii < i < ii
E. iii < ii < i
--------------------------------------------------------------------------------12. What is the percent carbon by mass in the compound below?
A. 39.4%
B. 42.2%
C. 51.7%
D. 56.3%
E. 62.3 %
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--------------------------------------------------------------------------------13. Select the electron-domain geometry and molecular geometry
of chlorine in the perchlorate ion, ClO4−.
A. Electron domain geometry trigonal planar molecular geometry tetrahedral B. trigonal planar trigonal planar C. tetrahedral tetrahedral D. trigonal pyramidal trigonal pyramidal E. trigonal pyramidal trigonal planar --------------------------------------------------------------------------------14. Which of the following molecules are isomers?
A. I and II only
B. II and III only
C. I and IV only
D. I, II, and III
E. All of them
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--------------------------------------------------------------------------------15. As bond order increases, the strength of a covalent bond
_________ and bond length ______________.
As bond order increases
strength A. increases length increases B. decreases decreases C. increases decreases D. decreases increases E. increases remains constant --------------------------------------------------------------------------------16. Which of the following have one or more atoms in the
structure that have exceptions to the octet rule?
BF3
NF3
SiF4
XeF4
A. BF3 and NF3
B. NF3 and SiF4
C. SiF4 and XeF4
D. BF3 and XeF4
E. NF3 and XeF4
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--------------------------------------------------------------------------------17. Which of the following contains the largest Y-X-Y bond
angle where X is the central atom of the molecule?
A. BF3
B. SiCl4
C. NH3
D. H2O
E. They all have the same bond angle.
--------------------------------------------------------------------------------18. Which of the following molecules has a trigonal planar
structure?
1. CO32−
2. SOCl2
3. H3O+
4. SO3
A. 1 only
B. 1 and 4
C. 1, 2 and 3
D. 1, 3 and 4
E. all 4
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--------------------------------------------------------------------------------19. Rank the indicated bond angles in the molecule shown below
in order of increasing bond angle. (Lone pairs are NOT
explicitly shown.)
A.
B.
C.
D.
E.
1
H
O
3
H
C
C
O
H
2
4
O
H
N
H
1<4<3<2
3<1<2≈4
4=1<2<3
4=1<2=3
3<4<1<2
--------------------------------------------------------------------------------20. What is the total number of σ and π-bonds in the following
molecule?
H−C ≡ C−C ≡ C−C ≡ N
A. B. C. D. E. σ 6 3 6 3 3 π 3 3 6 6 9 --------------------------------------------------------------------------------Go on to the next page
--------------------------------------------------------------------------------21. Which of the following molecules will exhibit delocalized πbonding?
I. SO
II. SO2
III. SO3
A. I only
B. II only
C. III only
D. I and II
E. II and III
--------------------------------------------------------------------------------22. Which one of these molecule has the smallest % oxygen by mass?
A. I
B. II
C. III
D. IV
E. I and IV have the same and the smallest % oxygen
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--------------------------------------------------------------------------------23. Draw Lewis structures for NO2+, NO2− and NO3−. Based on
the interpretation of the Lewis structures, put these in order of
increasing bond order?
A.
B.
C.
D.
E.
NO2+ < NO2− = NO3−
NO2+ < NO3− < NO2−
NO2− = NO3− < NO2+
NO3− < NO2− < NO2+
NO2− < NO2+ < NO3−
--------------------------------------------------------------------------------H
24.
H
CH
C
CH 3
OH
C
H
How are the molecules below related to the molecule shown
above? Are they a geometric isomer, a structural isomer or neither?
O
H
C
C
H
CH3
H
C
H 3C
CH
C
H
A. B. C. D. E. I neither neither geometric structural geometric OH
H 3C
C
H
CH
C
CH3
II
I
H
II structural geometric geometric structural structural C
H
H
III
III geometric structural structural geometric geometric --------------------------------------------------------------------------------Go on to the next page
OH
--------------------------------------------------------------------------------25. Which of the following are pairs of resonance structures?
A.
B.
C.
D.
E.
I only
II only
III only
I and II
II and III
--------------------------------------------------------------------------------26. What is the electron domain geometry of a molecule that only
contains S and F and is 29.67% S by weight?
A. Octahedral
B. Trigonal planar
C. Linear
D. Tetrahedral
E. Trigonal bipyramidal
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--------------------------------------------------------------------------------27. Which one of these correctly depicts hydrogen bonding in
acetic acid (CH3COOH)? The dashed line (
) represent
the hydrogen bond.
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Br
I
Br
I
i
ii.
iii.
174 °C
219 °C
285 °C
Cl
Cl
Boiling
point
28. The boiling points of the three molecules shown are given
below their structures. Which of these statements are true?
I.
The first molecule (i) has the greatest dipole
moment of the three.
II. As the polarity increases the boiling point increases.
III. As the London dispersion forces increase, the
boiling point increases.
A. I only
B. II only
C. III only
D. I and II
E. I and III
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CHEMISTRY 110 EXAM 2
February 25, 2013
Answer Key
FORM A
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
A
B
B
D
D
D
B
E
D
C
A
D
C
E
C
D
A
B
E
C
E
B
D
A
C
E
B, D and E = full credit
28. E