Chapter 9 - University of Dayton Academic Webserver

324
SF 6
Chapter 9: Molecular Structures
6 + 6(7)
= 48
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AX 6E 0
octahedral
octahedral
93. (a) Molecules of liquid methanol (CH 3 OH) interact via dipole-dipole interactions and hydrogen bonding.
These intermolecular forces must be overcome to evaporate liquid methanol.
H
H C
H
O
H
H
O
H
C
H
H
sp 3 d 2
(b) Decomposing molecules into other molecules requires breaking covalent bonds, so the forces that must
be overcome are the intramolecular (covalent) forces. The reactant molecule looks like this:
H
O O
H
and the product molecules look like this:
H O
H and O O .
So, all the polar covalent bonds in the reactants have to be broken to make some of the new bonds in
the products:
H
2 O O
2
H
H O
H
+
O O
(c) Molecules of solid urea (H 2 NCONH 2 ) interact via dipole-dipole interactions and hydrogen bonding.
Some of these intermolecular forces must be overcome to melt solid urea.
H
H
N C
O
N
H H
H
H
N C
O
N
H H
H
H
N C
O
N
H H