VERSION B
Chem 1C - Spring 2010 - exam 2
Yellow
ON YOUR SCANTRON:
 BUBBLE IN YOUR 7 DIDGIT PERM (Leaving the last three digits blank)
 BUBBLE IN THE VERSION: B
 WRITE YOUR NAME
AT THE END, HAND IN ONLY THE SCANTRON.
1234567
perm
version
name
1
1.
What is the molality of a solution of 150 g of NaI in 250 mL water, if the density
of water is 1 kg/liter?
(A)
(B)
(C)
(D)
(E)
2.
The sizes of the holes in a closest packed structure of ions with radius R are:
tetrahedral: 0.225 R
octahedral: 0.414 R
cubic: 0.732 R
Where would counterions with radius of 0.5 R most likely be?
(A)
(B)
(C)
(D)
(E)
3.
2
1
0.75
0.25
0.42
As you dilute a solution (adding solvent), which will decrease?
(A)
(B)
(C)
(D)
(E)
5.
in the tetrahedral holes
in the octahedral holes
in the cubic holes
in both tetrahedral and octahedral holes
in any of the holes
A solution contains 46 g of ethanol (C2H5OH) and 54 g of water. What is the
mole fraction of the ethanol?
(A)
(B)
(C)
(D)
(E)
4.
250 m
4m
400 m
15 m
60 m
mole fraction of solute
molality
molarity
all of the above
None of the above
Rank the following types of forces in order of increasing strength:
(A)
(B)
(C)
(D)
(E)
ionic < London < Dipole-dipole
London < Dipole-dipole < ionic
London < ionic < Dipole-dipole
ionic < Dipole-dipole < London
Dipole-dipole < London < ionic
2
6.
A 62.0 g sample of ethylene glycol antifreeze (a nondissociated, nonvolatile
solute with the formula C2H4(OH)2, molar mass 62) is dissolved in 180 g water.
What is the vapor pressure of this solution at 100°C?
(A)
(B)
(C)
(D)
(E)
7.
760 torr
76 torr
380 torr
1000 torr
691 torr
What is the freezing point of the above solution? (Kf = 1.8 oC kg/mol)?
−1 oC
+10 oC
−10 oC
−18 oC
−1.8 oC
(A)
(B)
(C)
(D)
(E)
8.
Pentane (C5H12) and hexane (C6H14) form an ideal solution. The vapor pressures
of pentane and hexane at 25° C are 500 torr and 150 torr, respectively. The mole
fraction of hexane in a pentane-hexane solution is 0.50. Calculate the mole
fraction of pentane in the vapor in equilibrium at 25° C with this solution.
(A)
(B)
(C)
(D)
(E)
9.
0.1
0.23
0.50
0.77
1
Solutions A and B of the same compound with equal volumes are placed in a
closed container. At the start the concentration of solution A is smaller than the
concentration of solution B. After a while the vapor pressure reaches equilibrium.
Now
A
(A)
(B)
(C)
(D)
(E)
B
the volumes are equal
beaker A is empty.
beaker B is empty.
the volume in Beaker A is larger than that in beaker B.
the volume in Beaker B is larger than that in beaker A.
3
10.
At a given temperature, you have a mixture of benzene (Pvap = 750 torr) and
toluene (Pvap = 300 torr). You do not know any of the mol fractions.
Nevertheless you are asked to pick the possible total vapor pressure from the
following choices:
(A)
(B)
(C)
(D)
(E)
11.
A cucumber is placed in a concentrated salt solution. What will most likely
happen?
(A)
(B)
(C)
(D)
(E)
12.
Salt will precipitate out.
Water will flow from the solution to the cucumber.
Salt will flow into the cucumber.
Water will flow from the cucumber to the solution.
No change will occur.
The unit cell in a certain lattice of atoms X and Y consists of a cube formed by an
X at each corner of the cube, an X at the center of the cube and a Y at the center
of each face. The empirical formula of the compound is:
(A)
(B)
(C)
(D)
(E)
13.
1050 torr
760 torr
500 torr
250 torr
150 torr
XY.
X5Y6.
X5Y3.
X2Y2.
X2Y3.
Doping Si with B or P would produce the following types of semiconductor:
(A)
(B)
(C)
(D)
(E)
B
P
n-type
n-type
p-type
n-type
n-type
p-type
p-type
p-type
none of the above
4
14.
What is the electron configuration of the Cr(III) ion in a complex?
(A)
[Ar]4s24d1
(B)
[Ar]3d14s2
(C)
[Ar]3d44s2
(D)
[Ar]3d3
(E)
[Xe]5d1
15.
The spectrochemical series is
I–< Br– < Cl– < F– < OH– < H2O < NH3 < en < NO2– < CN–
Which of the following complexes will absorb visible radiation of the highest
energy (shortest wavelength)?
(A)
(B)
(C)
(D)
(E)
16.
The color of a transition metal complex results from:
(A)
(B)
(C)
(D)
(E)
17.
bending vibrations.
stretching vibrations.
transition of an electron between d orbitals.
transition of an electron between s and p orbitals.
nuclear magnetic resonance.
Which ranking of the following compounds is in order of increasing
intermolecular forces:
(A)
(B)
(C)
(D)
(E)
18.
[Co(H2O)6]3+
[Co(I)6]3–
[Co(OH)6]3–
[Co(en)3]3+
[Co(NH3)6]3+
I2 < Cl2 < CO < H2O
Cl2 < I2 < CO < H2O
CO < I2 < H2O < Cl2
H2O < Cl2 < I2 < CO
H2O < I2 < CO < Cl2
Which of the following has the highest boiling point?
(A)
(B)
(C)
(D)
(E)
Xe
HCl
CO2
Benzene
F2
5
19.
Which of the following has the lowest freezing point?
(A)
(B)
(C)
(D)
(E)
20.
Xe
HCl
CO2
Benzene
F2
These two [Co(en)3] complexes are
(A)
(B)
(C)
(D)
(E)
linkage isomers
coordination isomers
stereo isomers
ionization isomers
none of the above
.
21.
A hypothetical element has atoms that weigh 10-26 grams each and form an FCC
crystal with a unit cell with a volume of 10-26 cm3. The crystal density is
(A)
(B)
(C)
(D)
(E)
22.
4 gram/ cm3
1026 gram/ cm3
1 gram/ cm3
2 gram/ cm3
0.25 gram/ cm3
How much energy does it take to melt 18 g of water at 0 oC (ΔHfus = 6 kJ/mol)?
(A)
(B)
(C)
(D)
(E)
103 J
6 x 103 J
106 J
3 x 106 J
18 x 106 J
6
23.
Which of the following is pentaamminechlorocobalt(III) chloride?
(A)
(B)
(C)
(D)
(E)
24.
Which of the following is polar?
(A)
(B)
(C)
(D)
(E)
25.
[Co(NH3)5Cl]Cl5
[Co(NH3)5Cl]Cl
[Co(NH3)6]Cl2
[Co(NH3)5Cl]Cl2
[Co(NH3)6]Cl5
F2
SF2
SF6
S2
None of the above
When a substance freezes, what are the signs of the enthalpy change, ΔH and
entropy change ΔS?
ΔH
ΔS
positive
positive
positive
negative
negative
positive
negative
negative
impossible to predict
(A)
(B)
(C)
(D)
(E)
26.
Larger intermolecular forces in a liquid lead to
(A)
(B)
(C)
(D)
(E)
27.
lower vapor pressure
larger viscosity
lower boiling point
(A)
and (b)
all of the above
How many electrons are involved in π bonding in benzene (C6H6):
(A)
(B)
(C)
(D)
(E)
6
12
18
24
30
7
28.
What is the hybridization of the carbon atoms in graphite?
(A)
(B)
(C)
(D)
(E)
29.
Which is closest to the bond angle in ozone, O3
(A)
(B)
(C)
(D)
(E)
30.
90o
109.5o
120o
180o
360o
The bond order of H2 is
(A)
(B)
(C)
(D)
(E)
31.
sp
sp2
sp3
sp3d
they are not hybedrized
0
0.5
1
1.5
2
The solubility of nitrogen in water is 1 10-5 mol/L at 0°C when the N2 pressure
above water is 0.75 atm. What is the solubility of N2 in water when the partial
pressure of nitrogen above water is 1.5 atm at 0°C
(A)
(B)
(C)
(D)
(E)
0.5 10-5 mol/L
1 10-5 mol/L
2 10-5 mol/L
1 10-10 mol/L
7.5 10-5 mol/L
8
32.
Consider the following Lewis structure, in which E is an unknown element
E can be
(A)
(B)
(C)
(D)
(E)
33.
H
P
Be
I
K
The allene molecule has the following Lewis structure:
Which of the following statements is false?
(A)
(B)
(C)
(D)
(E)
BONUS:
The center C atom is sp hybridized.
The center C atom is involved in two π bonds
The outer C atoms are sp2 hybridized
All four H atoms are in the same plane
The p orbitals on the center C atom are perpendicular to each other
To prevent crenation or hemolysis, IV (intravenous) solutions must be
(A)
(B)
(C)
(D)
(E)
Hypotonic
Hypertonic
Equimolar
Equidistant
Isotonic
Don’t forget perm, version B, name
9
10