Bonding practice problems
1) Which of the following statements is TRUE?
A) The Real World is still one of the best shows on television.
B) Energy is released when two like charged species are brought closer to one another.
C) Energy is given off when two oppositely charged species are separated.
D) The force between two ions is larger in water than in air or a vacuum.
E) The potential energy of oppositely charged particles decreases as they are brought closer
together.
1)
2) The most likely distance between two atoms involved in a bond is
A) determined primarily by the size of the nuclei.
B) generally larger as the bond energies become larger.
C) always larger for double and triple bonds.
D) not related to bond energies.
E) the distance where the potential energy of the interaction is at a minimum.
2)
3) Use the bond energies provided to estimate H°rxn for the reaction below.
ICl3(g) + 2 H2(g)
Bond
I-Cl
H-H
H-I
H-Cl
HI(g) + 3 HCl(g)
H°rxn = ?
Bond Energy (kJ/mol)
209
436
297
431
4) Use the bond energies provided to estimate H°rxn for the reaction below.
H2 O(g) + Cl2(g)
Bond
H O
Cl Cl
Cl O
H Cl
HOCl(g) + HCl(g)
4)
H°rxn = ?
Bond Energy (kJ/mol)
464
244
205
431
5) Use the bond energies provided to estimate H°rxn for the reaction below.
CH3OH(l) + 2 O2 (g)
Bond
C-H
C-O
C=O
O=O
O-H
3)
CO 2(g) + 2 H2O(g)
Bond Energy (kJ/mol)
414
360
799
498
464
1
H°rxn = ?
5)
6) Write the equation describing the lattice energy of Li2 O:
7) Write the equation describing the lattice energy of MgI2:
8) Identify the compound with the highest lattice energy.
A) NaCl
B) KCl
C) LiCl
9) Identify the compound with the highest melting point.
A) SrI2
B) MgF2
C) CaCl2
D) SrF2
10) Given the tabulated data, what is the lattice energy of calcium chloride?
Process
heat of sublimation for calcium
first ionization energy for calcium
second ionization energy for calcium
bond energy of chlorine (Cl2)
9)
E) SrBr2
10)
H° (kJ/mole)
193
590
1145
244
electron affinity for chlorine
heat of formation for calcium chloride
-349
-796
11) Given the tabulated data, what is the lattice energy of calcium iodide?
Process
heat of sublimation for calcium
first ionization energy for calcium
second ionization energy for calcium
bond energy of iodine (I2 )
8)
D) CsCl
11)
H° (kJ/mole)
193
590
1145
151
heat of sublimation for iodine (I2 )
15
electron affinity for iodine
heat of formation for calcium iodide
-295
-537
12) Given the tabulated data, what is the lattice energy of calcium oxide?
Process
heat of sublimation for calcium
first ionization energy for calcium
second ionization energy for calcium
bond energy of oxygen (O2 )
H° (kJ/mole)
193
590
1145
498
first electron affinity for oxygen
second electron affinity for oxygen
heat of formation for calcium oxide
-141
878
-635
2
12)
13) Choose the bond that is most likely the strongest.
A) N=O
B) N-I
C) N-O
D) N-S
E) N=N
13)
14) The description of covalent bond formation as an overlap of atomic (or hybrid atomic) orbitals is
known as:
A) overlap theory
B) atomic orbital theory
C) VSEPR
D) molecular orbital theory
E) valence-bond theory
14)
15) When more than one acceptable Lewis structure can be written for a given molecule it is said to
have _________________.
A) equal
B) polar
C) split
D) resonance
E) unstable
15)
16) According to valence bond theory, how many sigma bonds and pi bonds are in a triple bond.
A) 1 sigma, 1 pi
B) 2 sigma, 1 pi
C) 2 sigma, 2 pi
D) 1 sigma, 2 pi
16)
17) The hybridization of the central atom in the molecule SF5 - is __________.
17)
A) sp
B) sp2
C) sp3
D) sp3 d
E) sp3 d2
18) The hybridization of N in the nitrate ion is:
A) sp2
B) sp
C) spd
D) sp3
E) not hybridized
18)
19) What is the bond angle in water?
A) 104.5°
B) 107°
C) 109.5°
D) 120°
E) 180°
20) What are the bond angles in ammonia?
A) 104.5°
B) 107°
C) 109.5°
D) 120°
E) 180°
21) What is the formal charge of N in the radical, NO2 ?
A) -2
B) -1
19)
20)
21)
C) 0
D) +1
22) How many lone pairs are on the central atom of ozone (O3 )?
A) 0
B) 1
C) 2
D) can't determine
E) unpaired radical
3
E) +2
22)
23) Which of the following statements is INCORRECT concerning the carbonate ion?
A) the molecule has a trigonal planar geometry
B) the molecule has three stable resonance structures
C) the central carbon is sp2 hybridized
D) the formal charge of carbon is zero
E) one of the C-O bonds is stronger than others (the double bond)
23)
24) Which of the following resonance structures for OCN will contribute most to the resonance hybrid
of OCN ?
A) O(2 lone pairs)=C=N (2 lone pairs)
B) O(1 lone pair) C-N(3 lone pairs)
C) O(1 lone pair)=C(2 lone pair)=N(1 lone pair)
D) O(3 lone pairs)-C N(1 lone pair)
E) All resonance structures contribute equally to the resonance hybrid of OCN .
24)
25) According to molecular orbital theory, when two atoms bond together, their p orbitals combine to
form:
A) two sigma M.O.'s and two pi M.O.'s
B) four pi M.O.'s only
C) one sigma and one pi M.O.
D) two sigma M.O.'s and four pi M.O.'s
E) none of these
25)
26) Which of the following molecules is paramagnetic?
A) C2
B) B2
26)
C) N2
D) F2
E) none - all are diamagnetic
27) The "electron-sea" model for bonding in metals, does NOT do a good job explaining
A) electrical conductivity
B) malleability
C) shiny appearance
D) ductility
E) formation of gaseous diatomic metal molecules such as Li2
27)
28) Which of the following would you predict to have an overlapping conduction band and valence
band?
A) iodine crystals
B) solid CO2
C) solid silicon
D) crystalline rock salt
E) rubidium metal
28)
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29) Which of the following band diagrams corresponds to a semiconductor?
A)
B)
C)
29)
D)
30) Which of the following band diagrams corresponds to an electrical isulator?
A)
B)
C)
D)
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30)
31) Why is a material such as diamond an insulator?
A) There are no electrons in the valence band.
B) All of the electrons are in the conduction band.
C) Electrons cannot make the transition over the large energy gap between the valence band and
the conduction band.
D) The bonds in diamond are too strong to allow atoms to move so no current flows.
E) When I get a diamond, I feel like I have a warm blanket wrapped around me.
31)
32) Which of the following is FALSE?
A) Silicon has a small gap between its conduction band and its valence band.
B) Graphite has overlapping conduction and valence bands.
C) Elemental sulfur has a large gap between its conduction band and its valence band.
D) Electrical conductance requires that the solid have empty orbitals that are accessible to
electrons from lower energy levels.
E) Aluminum has a small gap between its conduction band and its valence band.
32)
33) What could you do to modify the semiconducting properties of the group 14 element below? (there
may be more than one way)
33)
A) Hit it with a hammer three times.
B) It already is an intrinsic semiconductor - don't mess with it.
C) Dope it with an electron donor from group 15 (n-type).
D) Dope it with an electron acceptor from group 13 (p-type).
E) There is no way to modify it.
TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false.
34) Valence bond theory describes covalent bonding as the overlap of partially filled atomic orbitals.
34)
35) The best way to predict the magnetic properties of a molecule is to draw its lewis structure and
look for any unpaired electrons.
35)
36) Molecular orbitals can be approximated by combining valence atomic orbitals using the linear
combinations of atomic orbitals (LCAO) method.
36)
37) Because molecular orbital theory correctly explains observations that valence bond theory cannot, it
is better, and the use of valence bond theory should be discouraged.
37)
38) Valence bond theory is a very useful and powerful theory that can be applied to a large number of
molecules. However, it cannot explain all observations.
38)
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39) The electrical conductivity of semiconductors increases with temperature.
39)
40) The electrical conductivity of metallic conductors increases with temperature.
40)
41) The electrical resistance of superconductors is very high at low temperatures.
41)
42) The electrical conductivity of superconductors is very high at low temperatures.
42)
43) Band theory can explain the properties of metallic conductors, semiconductors and insulators but
not superconductors.
43)
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