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10/29/2013
Review Unit #7 A.P.
Chemistry
Chapters #8 and #9
Topics for Review
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Lewis dot structures
Hybridization and shapes/angles
VSEPR
Polarity (dipole moments)
Electron Pair Geometry
Molecular Geometry
Bond energies
Resonance
Draw the Lewis dot structure. Label
the electron pair geometry, the
molecular geometry, the polarity
(using deltas), tell the bond angles
and tell the hybridization for SO2.
O
O
S
Electron pair geometry =
trigonal planar
Molecular Geometry =
v-shaped or bent
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10/29/2013
Bond Angles and Hybridization
Bond angles = <120o
Hybridization = sp2
Resonance & Polarity
δ-
δ-
O
O
δ-
δ-
O
O
S
S
δ+
δ+
What are the electron-pair
geometry and hybridization?
1.
2.
3.
4.
5.
SF6
H2CO
HCN
PF5
CH4
What are the electron-pair
geometry and hybridization?
1.
2.
3.
4.
5.
SF6
H2CO
HCN
PF5
CH4
Octahedral
Trigonal Planar
Linear
Trig. Bipyramidal
Tetrahedral
sp3d2
sp2
sp
sp3d
sp3
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10/29/2013
Find the ∆Hfo for the Reaction
• C2H4(g)
2 CH2(g)
• Answer = 2266 – 1652 = 614 kJ (endo)
• Draw the reactants, categorize the bonds and
calculate the amount of energy needed to break bonds
H
H
C=C
H
H 4 (C-H) + 1 (C=C)= 2266 kJ
• Draw the products and do the same…
H-C-H + H-C-H = 4 (C-H) = 1652 kJ
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