Perm number:
first letter of last name
Name_____________________________________
Chem 1C - Spring 2010 - exam 1
de Vries 4/21/2010
VERSION B
ON YOUR SCANTRON:
 BUBBLE IN YOUR 7 DIDGIT PERM (Leaving the last three digits blank)
 BUBBLE IN THE VERSION: A
 WRITE YOUR NAME
AT THE END, HAND IN BOTH THE SCANTRON AND THIS EXAM WITH
YOUR WORK.
1
1.
Which of these molecules has a permanent dipole:
(A)
H2
(B)
CH4
(C)
CO2
(D)
NH3
(E)
SF6
2.
Which of the following statements is correct:
(A)
A double bond is composed of two σ bonds
(B)
A triple bond is composed of three π bonds
(C)
σ bonds have most electron density on the internuclear axis
(D)
π bonds have electron density on the internuclear axis
(E)
Single bonds are stronger than multiple bonds
3.
Which of the following has two  bonds?
(A)
C2H2
(B)
C2H4
(C)
C2H6
(D)
C3H8
(E)
CH4
4.
Which of the following molecules has the strongest carbon-oxygen bond:
(A)
CO
(B)
CH3OH
(C)
CO2
(D)
CO32(E)
They are all equal
5.
Which has the most polar bond?
(A)
H-I
(B)
H-Br
(C)
H-H
(D)
H-F
(E)
All the same
6.
Which intermolecular force is the strongest?
(A)
London dispersion forces
(B)
Ion–ion interactions
(C)
Hydrogen bonding
(D)
Dipole–dipole forces
(E)
Impossible to predict
2
7.
Which of the following atoms is the most electronegative:
(A)
K
(B)
C
(C)
Mg
(D)
F
(E)
Cs
8.
Which atom has the following electron configuration: [Kr] 5s2 4d10 5p5
(A)
Br
(B)
H
(C)
Xe
(D)
In
(E)
I
9.
Which of the following molecules is polar?
(A)
H2
(B)
O2
(C)
CH4
(D)
H2O
(E)
BCl3
10.
Bond
H—H
F—F
H—F
Average bond energy (kJ/mol)
432
154
565
Given the average bond energies above, estimate ∆H for the following reaction:
H2 + F2  2HF
(A)
(B)
(C)
(D)
(E)
11.
̶ 21 kJ
21 kJ
̶ 544 kJ
544 kJ
1151 kJ
How many resonance structures does the molecule SO2 have?
(A)
0
(B)
1
(C)
2
(D)
3
(E)
4
3
For questions 12-22 the partial Lewis structure of C5H5O3Cl is shown below without
the lone pairs and with each carbon identified by a number and each oxygen atom
identified with a roman number.
12.
What is the total number of electrons that must be shown (including all bonds and
lone pairs) in the complete Lewis structure of this molecule?
(A)
32
(B)
36
(C)
38
(D)
42
(E)
50
13-17. What is the hybridization of the following atoms:
sp
sp2
sp3
not
hybridized
d2sp3
question 13
oxygen i
A
B
C
D
question 14
oxygen ii
A
B
C
D
question 15
carbon 1
A
B
C
D
question 16
carbon 3
A
B
C
D
question 17
carbon 4
A
B
C
D
E
E
E
E
E
4
18.
What is the three dimensional shape of the bonds around carbon atom 5?
(A)
linear
(B)
trigonal planar
(C)
tetrahedral
(D)
T shaped
(E)
seesaw
19.
What are the approximate angles between the bonds of oxygen atom iii?
(A)
0o
(B)
90o
(C)
109o
(D)
120o
(E)
180o
20.
How many non-bonding pairs of electrons should be shown on oxygen atom iii?
(A)
0 pairs
(B)
1 pair
(C)
2 pairs
(D)
3 pairs
(E)
none of the above
21.
How many π bonds are there between carbon atoms 1 and 2?
(A)
0
(B)
1
(C)
2
(D)
3
(E)
4
22.
How many σ bonds are there between carbon atoms 1 and 2?
(A)
0
(B)
1
(C)
2
(D)
3
(E)
4
5
This diagram refers to B2, C2 as well as N2
23.
Arrange B2, C2, and N2 in order of decreasing bond energy (consider bond order):
(A)
B2 > C2 > N2
(B)
B2 > N2 > C2
(C)
C2 > B2 > N2
(D)
C2 > N2 > B2
(E)
N2 > C2 > B2
24.
Which of the following is/are paramagnetic?
(A)
C2
(B)
N2
(C)
B2
(D)
C2 and N2
(E)
none of the above
25.
Which of the following have bond order 0.5?
(A)
He2 and Li2
(B)
H2¯, H2+ and He+
(C)
H2
(D)
B2
(E)
C2 and N2
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26.
How many σ and π bonds are there in benzene (C6H6)?
(A)
6 σ and 6 π
(B)
12 σ and 6 π
(C)
6 σ and 3 π
(D)
12 σ and 3 π
(E)
6 σ and 12 π
27.
What is the measure of the bond angle between the C-Cl bonds in the molecule
Cl2CO?
(A)
Exactly 109.5o
(B)
Exactly 120°
(C)
Slightly less than 120o
(D)
Exactly 180°
(E)
Slightly less than 180o
28.
An electromagnetic wave with frequency of 5 x 1014 s-1 has a wavelength of:
(A)
100 nm
(B)
166 nm
(C)
300 nm
(D)
500 nm
(E)
600 nm
(Note: λν = c, the speed of light is 3 x 108 m/s and 1 nm = 10-9 m.)
29.
The majority of electron transitions in molecules occur in the _________ region
of the electromagnetic spectrum.
(A)
radiowave
(B)
UV or visible
(C)
microwave
(D)
IR
(E)
X-ray
30.
Infra red light may excite
(A)
electronic transitions
(B)
vibrations in any molecule
(C)
vibrations in molecules with a permanent or dynamic dipole
(D)
none of the above
(E)
all of the above
31.
What type(s) of intermolecular forces is (are) exhibited by methane (CH4)?
(A)
ionic forces
(B)
Hydrogen bonding
(C)
Dipole–dipole forces
(D)
London dispersion forces
(E)
No forces at all
7
32.
Which of the following has the lowest boiling point?
(A)
N2
(B)
HF
(C)
KI
(D)
H2O
(E)
NaCl
33.
MRI is a medical imaging technique, based on:
(A)
vibrational spectroscopy
(B)
nuclear magnetic resonance spectroscopy
(C)
rotational spectroscopy
(D)
microscopy
(E)
microwave spectroscopy
34.
BONUS QUESTION
We put no more than two electrons (spin up and spin down) in an
orbital. This is based on the exclusion principle which was
formulated by which person pictured on the left:
(A)
(B)
(C)
(D)
(E)
Wolfgang Pauli
Avogadro
George Washington
Heisenberg
Einstein
Don’t forget perm, version, name!
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