Intermolecular Forces: Lewis Structures Get Sticky!
1.
First, draw the Lewis structure AND indicate the geometry for each of the compounds below. Second, identify
the intermolecular forces that must be overcome to convert each of the following from a liquid to a gas:
Br2
CH3OH
H 2S
2. Complete the Lewis structures below, then explain why ethanol has a higher boiling point (78.4°C) than
methanol (64.7°C).
H
H H
Ethanol:
H C
C O H
H H
Methanol:
H C O H
H
3. First, draw the Lewis structure AND indicate the geometry for each of the following compounds. Then rank
the following four substances from lowest to highest anticipated boiling point: CH3OCH3, Ne, C2H4, CH4
4. Motor oil largely consists of molecules that consist of long chains of carbon atoms with hydrogen atoms
attached to them. Using your knowledge of intermolecular forces, explain why it wouldn’t be better to use a
compound like glycerol. The formula of glycerol is
H OH H
HO C C C H
H H OH
5. Put the following molecules in order of increasing boiling point (Hint: You might want to draw out the Lewis
structures before deciding on the arrangement): GeCl4, CH4, SiCl4, SiH4, GeBr4
6. Circle the compound in each of the following pairs that has the larger London dispersion forces.
a.
H2O or H2S
b. N2 or O2
c. CH4 or CCl4
7. First, draw the Lewis structure AND indicate the geometry for each of the following four compounds. Then,
CIRCLE the compounds that can form intermolecular hydrogen bonds with other molecules of the same kind.
CH3F
CH3NH2
CH3OH
CH3Br
8. Identify all of the intermolecular forces that are present in each of the following substances and circle the
substance in each pair that has the higher boiling point.
a.
C6H14 or C8H18
b. C3H8 or CH3OCH3
c.
CH3OH or CH3SH
d. NH2NH2 or CH3CH3