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Review for Chapter 8,9
AP Chemistry
Essential Questions: You should be able to answer the following essential learning questions at the
end of Chapters 8 and 9.
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What is the difference between inter and intra molecular bonding?
How many types of intra molecular bonding are there and how do types of bonding affect the
properties of substances such as their physical states, melting and boiling points and their
reactivity?
What are Lewis structures and how is resonance linked to the Lewis structures?
What is the significance of formal charge? How does the formal charge help in figuring out the
Lewis structure?
How is the polarity of a molecule gauged? What implications does polarity of a molecule has on
the properties of a molecule?
What is the connection between Lewis structures, hybridization and valence bond theory?
What are hybrid orbital and valence theories? How do they explain 3D structure of the bonded
molecules?
What are bond angles? How do you determine the bond angles?
What are the sigma and pi bonds? What are the localized and the delocalized electrons? What is
the relationship between the stability of a compound and delocalization of the electrons?
Your own question (s)….
Connections to the real-world and other Chemistry Units
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Give two examples of real-life situations where knowledge of VSEPR structures or bonding
comes in handy.
How do we smell? How is smell related to the 3D structure of the “smelly” substances?
You will be using knowledge of VSEPR and Hybridization in organic chemistry and bonding is
used throughout various chapters in chemistry.
Anything else?
(level 1)
Bookwork Problems:
Ch 8 PS: 14,17,23,33, 43, 53c, d, 57, 63 d, e, 79
Ch 9 PS: 8, 10, 16, 20 (and draw overall dipole moments), 30, 34, 36, 41, 59, 73; Recommended #9, 11,
13, 19, 25, 31, 40, 55, 60
(level 2)
1. Use partial orbital diagrams to describe how mixing of atomic orbitals on the central atoms leads to the
hybrid orbitals in each of the following:
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2012
a) Methanol, CH3OH
b) Sulfur tetrafluoride, SF4
2. Rank the bonds in each set in order of increasing length and bond strength:
N=N, N—N, N≡N
3. Born-Haber cycles were used to obtain the first reliable values for electron affinity by considering the
EA value as the unknown and using a theoretically calculated value for the lattice energy. Use a BornHaber cycle for KF and the following values to calculate a value for the electron affinity of fluorine:
K(s)K (g) ΔH =90 kJ
K(g) K+ + e- ΔH=419 kJ
F2 (g)  2F (g) ΔH=159 kJ
K(s) + 1/2F2(g)  KF (s) ΔHf°=-569 kJ
K+ (g) + F- (g)  KF(s) ΔHlattice=-821kJ
4. Formic acid (HCOOH) is secreted by certain species of ants when they bite. It has this structural
formula:
Rank the relative strengths of the C-O bond, C=bond
5. Draw/write the following for CNSa. Draw at least two possible Lewis Structures. Find the best structure by using formal charges.
b. Type of molecule (ABE?)
c. Electron Domain Geometry
d. Molecular Geometry
e. Bond Angle
f. Hybrid Orbital Diagram
Key:
Use partial orbital diagrams to describe how mixing of atomic orbitals on the central atoms leads to the
hybrid orbitals in each of the following:
c) Methanol, CH3OH
d) Sulfur tetrafluoride, SF4
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Solution:
a) For the hybridized C atom: 2p (one arrow in each of two boxes) and 2s (filled) mix to sp3 (one
arrow in each of the four boxes); For the hybridized O atom: 2p (4 arrows) and 2s (filled) mix to
sp3 (4 boxes with a total of 6 arrows)
b) For the hybridized S atom: 3d (empty), 3p (4 arrows) and 3s (filled) mix to sp3d (5 boxes with a
total of 6 arrows)
2. Rank the bonds in each set in order of increasing length and bond strength:
a)
N=N, N—N, N≡N
Bond length: N≡N< N=N< N—N
Bond strength: N—N< N=N< N≡N
3. Born-Haber cycles were used to obtain the first reliable values for electron affinity by considering the
EA value as the unknown and using a theoretically calculated value for the lattice energy. Use a BornHaber cycle for KF and the following values to calculate a value for the electron affinity of fluorine:
K(s)K (g) ΔH =90 kJ
K(g) K+ + e- ΔH=419 kJ
F2 (g)  2F (g) ΔH=159 kJ
K(s) + 1/2F2(g)  KF (s) ΔHf°=-569 kJ
K+ (g) + F- (g)  KF(s) ΔHlattice=-821kJ
-336 kJ
4. Formic acid (HCOOH) is secreted by certain species of ants when they bite. It has this structural
formula:
Rank the relative strengths of the C-O bond, C=bond
C=O is greater than C-O
5. Draw/write the following for CNSa. Draw at least two possible Lewis Structures. Find the best structure by using formal charges.
b.Type of molecule (ABE?)
c. Electron Domain Geometry
d. Molecular Geometry
e. Bond Angle
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f. Hybrid Orbital Diagram
a.
credit: google images
b. Linear
c. Linear
d. 180
e. 180
f. sp hybridized c atom in the middle sigma bonded to p orbitals of N and S. One pi bond on each side of
C . One pi bond between C and N and other pi bond between C and S.
Level 3: AP Workbook Ch 2