CHEMISTRY 110 EXAM 2
Oct. 11, 2010
FORM A
--------------------------------------------------------------------------------1. What is the empirical formula that corresponds to a compound that
contains only 57.69% carbon, 30.77% oxygen, and 11.54%
hydrogen?
A.
B.
C.
D.
E.
C5H12O2
C2.5H6O
C3H12O2
C58H12O31
C6HO3
------------------------------------------------------------------------------------3. To which class of compounds does the molecule shown below belong?
A.
B.
C.
D.
E.
alcohols
aromatics
alkanes
alkenes
alkynes
------------------------------------------------------------------------------------4. What is the electron domain geometry of the [TeF5]! anion?
--------------------------------------------------------------------------------2. What is the weight percentage of nitrogen in urea [(NH2)2CO]?
A.
B.
C.
D.
E.
46.7%
31.8%
23.3%
48.3%
63.6%
A.
B.
C.
D.
E.
octahedral
trigonal bipyramidal
square planar
seesaw
square pyramidal
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------------------------------------------------------------------------------------5. A hydrocarbon consists of 85.7% C by mass. It has one double bond
and it is not heavier than oxygen [O2]. What is the molecular
formula of that hydrocarbon?
A.
B.
C.
D.
E.
------------------------------------------------------------------------------------7. Which of the following organic molecules have the same empirical
formula as cyclohexane?
cyclohexane
CH2
C2H 2
C2H 4
C2H 6
C3H 6
A
B
C
D
E
------------------------------------------------------------------------------------8. Which of the following molecules is a carboxylic acid?
------------------------------------------------------------------------------------6. Which molecule or molecules has free rotation about the bond
between the carbon atoms?
O
HO
A.
B.
C.
D.
E.
C2H 6
C2H 4
C2H 2
i only
ii only
iii only
ii and iii only
i, ii, and iii
N
H
HO
B
A
i.
ii.
iii.
H
O
O
C
D
E
------------------------------------------------------------------------------------9. Which one of the following molecules has square planar molecular
geometry?
A.
B.
C.
D.
E.
CCl4
XeF4
PH3
XeF2
SF4
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------------------------------------------------------------------------------------10. Arrange the following in order of increasing C – C bond length.
1. C2H2
A.
B.
C.
D.
E.
2. C2H6
3. C2H4
------------------------------------------------------------------------------------12. For the following three species, order their H#N#H bond angles
from the smallest to the largest.
4. C6H6 "
2<3<4<1
1<4=3<2
1<4<3<2
2<3<1<4
1<3<4<2
NH2!
amid
A.
B.
C.
D.
E.
NH3
NH4+
NH3
NH2!
NH2!
NH4+
ammonium
NH3
ammonia
<
<
<
<
<
NH2!
NH3
NH4+
NH3
NH4+
<
<
<
<
<
NH4+
NH2!
NH2!
NH4+
NH3
------------------------------------------------------------------------------------13. Which of the following molecules has a non-zero net dipole moment?
------------------------------------------------------------------------------------11. Which of these statements are true for a typical double bond?
i.
A double bond between two atoms is stronger and shorter
than a single bond between the same two atoms.
ii. A double bond consists of one ! bond and one " bond.
iii. There is no free rotation about a double bond.
A.
B.
C.
D.
E.
i only
i and ii
ii and iii
i and iii
All of the above statements are true.
-------------------------------------------------------------------------------------
A.
B.
C.
D.
E.
BF3
CO2
CS2
CH3OH
PF5
------------------------------------------------------------------------------------14. Which substance has ONLY London dispersion forces as an
intermolecular force?
A.
B.
C.
D.
E.
CaCl2
HBr
CH3CH3
CH3COOH
NH3
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--------------------------------------------------------------------------------15. How many atoms are in a 31.6 g sample of ammonium nitrate?
A.
B.
C.
D.
E.
1.21 $ 1024 atoms
1.75 $ 1024 atoms
2.14 $ 1024 atoms
2.38 $ 1023 atoms
2.67 $ 1024 atoms
A.
B.
C.
D.
E.
------------------------------------------------------------------------------------16. What are the hybridizations of carbons labeled 1 and 2 in a caffeine
molecule (shown below)?
O
A.
1
N
N
O
2
N
N
Hybridization of
carbon 1
carbon 2
sp2
sp2
3 2
------------------------------------------------------------------------------------17. How many % and & bonds are in acetonitrile, CH3CN?
3
B.
sp d
sp
C.
sp2
sp3
D.
sp3
sp2
E.
sp3
sp3
-------------------------------------------------------------------------------------
3 % and 3 & bonds
4 % and 2 & bonds
4 % and 3 & bonds
5 % and 3 & bonds
5 % and 2 & bonds
------------------------------------------------------------------------------------18. Which of the following species exhibits delocalized bonding?
A.
B.
C.
D.
E.
H2CO
NO2!
N 2H 2
CH3CH=CH2
CH3CH2CH3
------------------------------------------------------------------------------------19. Liquid methanol (CH3OH) evaporates quickly at room temperature.
To convert methanol from a liquid to a gas, which intermolecular
interactions must be overcome?
A. London dispersion forces only
B. London dispersion forces and dipole-dipole forces
C. London dispersion forces, dipole-dipole forces, and hydrogen
bonding
D. London dispersion forces and ion-dipole forces
E. Hydrogen bonding only
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------------------------------------------------------------------------------------20. Glucose, C6H12O6 is a simple carbohydrate. Which statement is
correct?
A. A mole of glucose has larger mass, but fewer molecules than a
mole of water (H2O).
B. A mole of water has equal mass to a mole of glucose.
C. A mole of glucose has 6 times as many oxygen atoms as a
mole of water.
D. The mass of a mole of glucose is 6 times larger than the mass
of a mole of water.
E. A mole of water has the same number of hydrogen atoms as a
mole of glucose.
------------------------------------------------------------------------------------21. A compound made up of only iodine and chlorine contains 45.59%
chlorine by mass. Assuming that the empirical formula equals the
molecular formula of this compound, what is the hybridization of
the central atom of this compound?
A.
B.
C.
D.
E.
------------------------------------------------------------------------------------22. Which one of the following molecules is the geometrical isomer of
cis-3,4-dimethyl-3-hexene shown below?
A
B
C
D
E
sp
sp2
sp3
sp3d
sp3d2
-------------------------------------------------------------------------------------
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------------------------------------------------------------------------------------23. Which approximate H#N#H and H#C#H bond angles describe
the structure of CH3CH2NH2, the best?
A.
B.
C.
D.
E.
H#N#H
109.5o
109.5o
120o
120o
< 109.5o
H#C#H
120o
< 109.5o
109.5o
< 109.5o
109.5o
-------------------------------------------------------------------------------------25. Which statement about the following molecule is false?
F
C
A.
B.
C.
D.
F
The hybridization of both of the carbon atoms is sp2.
The molecule shown above has 5 % bonds and 1 & bond.
The F#C#H bond is less than 120°.
The molecule shown above does NOT have a net dipole
moment.
The structure shown below is a geometrical isomer of the
molecule above.
------------------------------------------------------------------------------------24. Consider the neutral molecule with the molecular formula ClOF3.
Chlorine is the central atom and the remaining four atoms are directly
bonded to Cl. One of the F#Cl#F angles in this molecule is 175°
(i.e. approximately 180°). Based on this information, select the
incorrect statement from the choices below.
-------------------------------------------------------------------------------------
C
H
E.
A. The molecular geometry of ClOF3 is best described as
approximately square planar.
B. ClOF3 has one non-bonding electron pair on Cl.
C. The three O#Cl#F angles in this molecule are
approximately 90°, 90°, and 120°.
D. The hybridization of the Cl atom is sp3d.
E. Every Lewis structure that can be drawn for ClOF3 violates
the octet rule.
H
H
F
C
H
C
F
------------------------------------------------------------------------------------26. A 0.1014 g sample of purified fructose (which contains only C, H
and O) was combusted to produce 0.1486 g of CO2 and 0.0609 g of
H2O. What was the mass of oxygen in the fructose sample?
A.
B.
C.
D.
E.
0.0068 g
0.0406 g
0.0540 g
0.0812 g
0.5320 g
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------------------------------------------------------------------------------------27. Tetrahydrocannabinol (THC) is the main psychoactive component
of the cannabis plant. Its structure is shown below. Which of the
following statements is false.
------------------------------------------------------------------------------------28. Which of the following molecular geometries cannot be observed in
a molecule, for which the central atom is sp3d hybridized?
E
C
D
OH
B
A
A.
B.
C.
D.
E.
O
The angle labeled A is approximately 109.5°.
The angle labeled B is 120°.
The oxygen atom labeled C is sp hybridized.
The carbon atom labeled D is sp2 hybridized.
The carbon atom labeled E is sp3 hybridized.
-------------------------------------------------------------------------------------
trigonal planar
A
linear
B
T-shape
seesaw
C
D
trigonal
bipyramidal
E
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END OF EXAM
CHEMISTRY 110 EXAM 2
OCTOBER 11, 2010
Answer Key
FORM A
1. A
2. A
3. E
4. A
5. C
6. A
7. A
8. A
9. B
10. E
11. E
12. D
13. D
14. C
15. C
16. A
17. E
18. B
19. C
20. C
21. D
22. E
23. E
24. A
25. E
26. C
27. C
28. A