Chemistry 101 BOPS #3 pp. 1
Los Angeles City College
Chemistry 101 Bonus Opportunity Problem Set #3
Professor Torres
Directions: (20 pts. total; 0.5 pts. each) Use the appropriate Scantron to mark the correct
answers to the multiple-choice questions listed below. You MUST INCLUDE YOUR
WORK when submitting your final answers to receive any credit. Only consult your
notes and textbook for assistance.
1.
Use a Born-Haber cycle to calculate the lattice enthalpy of silver chloride from
the following data:
enthalpy of formation of Ag(g): +284 kJ/mol
first ionization energy of Ag(g): +731 kJ/mol
enthalpy of formation of Cl(g): +122 kJ/mol
electron affinity of Cl(g): +349 kJ/mol
enthalpy of formation of AgCl(s): -127 kJ/mol
A.
B.
C.
D.
E.
2.
Which of the following is expected to have a tetrahedral shape?
A.
B.
C.
D.
E.
3.
1613 kJ/mol
915 kJ/mol
1037 kJ/mol
1359 kJ/mol
661 kJ/mol
H2O
NH3
CH2Cl2
PCl3
SF6
Which of the following contains two π-bonds?
A.
B.
C.
D.
E.
N2
CH2CH2
CH3COOH
Fe2O3
C6H6 (benzene)
Chemistry 101 BOPS #3 pp. 2
4.
Arrange the following in order of increasing boiling point: NaCl, CO2, CH3OH,
CH3Cl.
A.
B.
C.
D.
E.
5.
CH3Cl, CO2, CH3OH, NaCl
CO2, CH3Cl, CH3OH, NaCl
CO2, CH3OH, CH3Cl, NaCl
NaCl, CH3OH, CH3Cl, CO2
CH3OH, CO2, CH3Cl, NaCl
For H2C=CH2(g) + H2(g) → H3C-CH3(g), predict the enthalpy given the
following bond dissociation energies:
H-C, 413 kJ/mol
C-C, 348 kJ/mol
A.
B.
C.
D.
E.
6.
its critical point occurs at a temperature above room temperature.
its triple point occurs at a pressure below atmospheric pressure.
its triple point occurs at a pressure above atmospheric pressure.
its critical point occurs at a pressure above atmospheric pressure.
its critical temperature is above its normal boiling point.
A linear molecule can have the general formulas AA, AB, or AB2. Given a
molecule with the general formula AB2, which one of the following would be the
most useful in determining whether the molecule was bent or linear?
A.
B.
C.
D.
E.
8.
–656 kJ/mol
–343 kJ/mol
–289 kJ/mol
–124 kJ/mol
–102 kJ/mol
Under ordinary conditions, a substance will sublime rather than melt if
A.
B.
C.
D.
E.
7.
H-H, 436 kJ/mol
C=C, 614 kJ/mol
Ionization energies
Electron affinities
Dipole moments
Electronegativities
Bond energies
Which of the following molecules is NONPOLAR?
A.
B.
C.
D.
E.
N2O
NF3
H2Se
TeO3
H2SO4
Chemistry 101 BOPS #3 pp. 3
9.
Determine the hybridization of sulfur in SF5-.
A.
B.
C.
D.
E.
10.
Which of the following is true when the C=C and C≡C bonds are compared?
A.
B.
C.
D.
E.
11.
low viscosity, low boiling point, and low heat of vaporization
high viscosity, low boiling point, and low heat of vaporization
low viscosity, high boiling point, and low heat of vaporization
low viscosity, low boiling point, and high heat of vaporization
high viscosity, high boiling point, and high heat of vaporization
Sulfur forms the following compounds: SO2, SF6, SCl4, SCl2. Which
hybridization is NOT represented by these molecules?
A.
B.
C.
D.
E.
13.
The triple bond is shorter than the double bond.
The double bond vibrates at a lower frequency than the triple bond.
The double-bond energy is lower than the triple-bond energy.
Both are composed of sigma and pi bonds.
All of the above are true.
A liquid substance that exhibits low intermolecular attractions is expected to have
A.
B.
C.
D.
E.
12.
dsp3
sp
d2sp3
sp3
sp2
sp
sp2
sp3
dsp3
d2sp3
Which of the following has the fewest pi bonds and is nonpolar?
A.
B.
C.
D.
E.
C2H2
CO2
CO3-2
N2
SO2
Chemistry 101 BOPS #3 pp. 4
14.
When the following compounds are kept at the same temperature, the compound
expected to evaporate most quickly is
A.
B.
C.
D.
E.
15.
Which of the following is expected to be the most soluble in hexane?
A.
B.
C.
D.
E.
16.
D.
E.
It will take longer because of the lower boiling temperature of the water.
It will take longer because of the higher boiling temperature of the water.
It will take less time because of the higher boiling temperature of the
water.
It will take less time because of the lower vapor pressure of the water.
It will take the same amount of time, regardless of the altitude.
The critical temperature of a substance is the
A.
B.
C.
D.
E.
18.
KCl
C2H5OH
C6H6
H2O
CH3COOH
How will the time it takes to hard-boil an egg compare at higher altitudes?
A.
B.
C.
17.
C8H18
C8H17OH
C8H17NH2
C6H14
C7H15COOH
temperature at which the vapor pressure of the liquid equals normal
atmospheric pressure.
highest temperature at which a substance can exist in the liquid state,
regardless of pressure.
temperature at which boiling occurs at 1.0 atmosphere of pressure.
temperature and pressure where solid, liquid, and vapor phases are all in
equilibrium.
point at which pressure and temperature are less than 0.
Which of the following would most likely have the highest boiling point?
A.
B.
C.
D.
E.
NH3
CH4
PCl5
HF
LiCl
Chemistry 101 BOPS #3 pp. 5
19.
Which of the following is true at the triple point of a pure substance?
A.
B.
C.
D.
E.
20.
Which of the following explains why, at room temperature, I2 is a solid, Br2 is a
liquid, and Cl2 is a gas?
A.
B.
C.
D.
E.
21.
soft, has a low melting temperature, and is a good electrical conductor.
hard, has a high melting temperature, and is a good electrical conductor.
soft, has a low melting temperature, and is a poor electrical conductor.
hard, has a high melting temperature, and is a poor electrical conductor.
soft, has a high melting temperature, and is a poor electrical conductor.
When the liquid metal mercury, Hg, is placed in a small tube, the meniscus
actually curves upward, just the opposite of water. The reason for this is that
A.
B.
C.
D.
E.
23.
hydrogen bonding
hybridization
ionic bonding
resonance
London dispersion forces
A crystal of NaCl is
A.
B.
C.
D.
E.
22.
The temperature is equal to the normal melting point.
All three states have identical densities.
The solid-liquid equilibrium will always have a positive slope moving
upward from the triple point.
The vapor pressure of the solid phase always equals the vapor pressure of
the liquid phase.
The pressure is exactly one-half the critical pressure.
the cohesive force is greater than the adhesive force.
the adhesive force is greater than the cohesive force.
the density of mercury is much larger than water.
the density of mercury is much greater where it is in contact with the
glass.
mercury is less volatile than water.
Which of the following species is NOT planar?
A.
B.
C.
D.
E.
CO32NO3ClF3
BF3
PCl3
Chemistry 101 BOPS #3 pp. 6
24.
CCl4, BeF2, PCl3, SbCl5, XeF4
Which of the following does not describe any of the molecules above?
A.
B.
C.
D.
E.
25.
Which of the following has a dipole moment of zero?
A.
B.
C.
D.
E.
26.
2500 cal
4433 cal
7445 cal
8255 cal
9555 cal
The boiling point of HCl(l) is higher than the boiling point of Ar(l) as a result of
A.
B.
C.
D.
E.
28.
HCN
NO2
SO2
SbF5
AsF3
How much heat is necessary to convert 10.0 g of ice at –10.0 °C to steam at 150.0
°C? The specific heat capacity of ice is 0.500 cal/g °C. The heat of fusion of ice
is 76.4 cal/g. The specific heat capacity of water is 1.00 cal/g °C. The heat of
vaporization of water is 539 cal/g. The specific heat capacity of steam is 0.482
cal/g °C.
A.
B.
C.
D.
E.
27.
Linear
Octahedral
Square planar
Tetrahedral
Trigonal pyramidal
hydrogen bonding.
higher formula mass.
stronger London forces.
permanent dipole forces.
ion-dipole forces.
Which of the following only has bond angles of 90° and 180°?
A.
B.
C.
D.
E.
IF5
BrF3
BCl3
NO3ICl4+
Chemistry 101 BOPS #3 pp. 7
29.
The bond order of N22+ is
A.
B.
C.
D.
E.
30.
2.5
1
2
1.5
3
Germanium is a semiconductor. Which of the following should be added in small
amounts to produce a p-type semiconductor?
A.
B.
C.
D.
E.
Bi
As
P
Sb
B
For Questions 31 – 32, consider the chemical formula for azidocarbonamide,
H2NC(O)NNC(O)NH2 (you need to draw this out yourself!)
31.
What is the approximate NNC bond angle in azidocarbonamide?
A.
B.
C.
D.
E.
32.
How many σ- and π-bonds, respectively, are there in the Lewis structure of
azidocarbonamide?
A.
B.
C.
D.
E.
33.
118°
180°
90°
107°
109°
14 and 3
15 and 3
14 and 2
8 and 3
11 and 3
The experimental observation that B2 has two unpaired electrons indicates that, in
molecular orbital ideas,
A.
B.
C.
D.
E.
the 2pB orbitals lie above the 2pσ orbital in energy.
the 2pπ orbitals lie below the 2pσ orbital in energy.
the 2pπ* orbitals lie below the 2pσ* orbital in energy.
the 2pπ orbitals are nonbonding.
the 2pπ* orbitals lie above the 2pσ* orbital in energy.
Chemistry 101 BOPS #3 pp. 8
Questions 34 – 38 refer to the following descriptions of bonding in different types of
solids.
A.
B.
C.
D.
E.
Lattice of positive and negative ions held together by electrostatic forces
Closely packed lattice with delocalized electrons throughout
Strong single covalent bonds with weak intermolecular forces
Strong multiple covalent bonds (including π-bonds) with weak
intermolecular forces
Macromolecules held together by strong covalent bonds
34.
Cesium chloride, CsCl(s)
35.
Gold, Au(s)
36.
Carbon dioxide, CO2(s)
37.
Methane, CH4(s)
38.
Silicon dioxide, SiO2(s)
For Questions 39 – 40, consider the structure of N,N-dimethylformamide shown below:
O 1
2
C
H
39.
N
CH3
Consider the nitrogen atom labeled “1”. Determine the molecular geometry of
this central atom.
A.
B.
C.
D.
E.
40.
CH3
trigonal planar
tetrahedral
trigonal pyramidal
bent
T-shaped
Estimate the O-C-H bond angle labeled “2” on the structure above.
A.
B.
C.
D.
E.
perfectly 120°
less than 120°
greater than 120°
less than 109.5°
greater than 109.5°