Note: Provide students with the formula of propylene,
CCHCH. (1-propene) for question 8.
2
H
How many repeating units are found in each of the
following structures?
a. a monomer
b. a dimer
Draw an electron-dot diagram and structural for
mula for each of these molecules:
a. propane
a.
a. Monomer: one
c. a trimer
b. Dimer: two
c. Trimer: three
d. a polymer
d. Polymer: many
b. propene
c. propyne
H
H H H
:
H C:C:C:H
H
b.
HH
H: C: C:: C: H
ii
Examples of natural polymers are starch, wool, silk,
linen, cellulose, and cotton. Examples of synthetic
polymers are synthetic fabrics, such as dacron, polyester, and nylon. Examples of plastics are polyethylene,Teflon, and PET.
H
ii
—
I
H
H
C
I
C
—
C
H
—
H
H
H
H : C : C ::: C :
H
—
—
=
—
H
11
What structural features make the properties of
one polymer different from those of another?
The monomers that make up the polymer determine
the properties.
I
HH
H
c.
H
H—C—C—C—
jj jj j4
List four examples of natural polymers and four
examples of synthetic polymers.
H
I
Use structural formulas to illustrate the polymerization that results in polypropylene.
Q
=
Q
—C —C
—
List two techniques that can be used to modify the
characteristics of a polymer. Explain each.
The addition of molecules that act as internal lubricants for the polymer chains makes the polymer more
flexible. Untreated polyvinyl chloride (PVC) is used in
rigid pipes and house siding. With added lubricant,
polyvinyl chloride becomes flexible enough to be used
in raincoats and shoes.
Polymer strength and toughness can be controlled by arranging the polymer chains so they lie
generally in the same direction. Then the chains are
stretched so that they uncoil. Strong films like the
polyethene used in plastic bags or the polyacrylonitrue found in fabrics are examples.
Alkanes are saturated hydrocarbons. There is no
double bond to be broken.
Why is the term unsaturated used to describe the
structures of alkynes and alkenes?
Draw a structural formula for both a saturated and
an unsaturated form of C
.
8
H
4
Alkenes and alkynes are characterized as unsaturated
because they contain double and triple covalent
bonds, which can undergo addition reactions.
Four arrangements of C
8 are possible, cyclobutane
H
4
is the only saturated isomer.
Rank the following in order of decreasing reactivity:
alkyne, alkane, and alkene. Explain your answer.
Increasing reactivity: alkane, alkene, and alkyne. The
addition of atoms to double and triple covalent bonds
occurs readily.
C
C
propylene
(propene)
polypropylene
Explain why alkanes cannot be used to make
polymers.
In what ways are cycloalkanes different from aro
matic compounds?
Cycloalkanes are saturated hydrocarbons in which
the carbon atoms are joined in a ring. Aromatic com
pounds are unsaturated hydrocarbons in which the
carbon atoms are joined in a ring.
C—CH=CH—CH.
3
H
2-butene
C = CH
2
H
—
3
CH
1 -hutene
C
2
H
—
2
CH
C—CH
2
H
9
2-rnethylpropene
Unit 3
C=CH—CH,—CH
9
H
3
Petroleum: Breaking and Making Bonds
cyclobutane
did aromatic compounds get their name?
ih discoverY of aromatic compounds found that
lwi had pleasant odors.
‘thy is the
ithin-a exagon representatbol
nzene molecule a better model than the hexagon
ternatiflg double bonds?
jh 1
lectrofls in covalent double bonds Ofl the carbuns are distributed equally around the ring
ir
Write the structural formula for a molecule con
ig at least three carbon atoms that represents (i)
ohol, (ii) an organic acid, and (iii) an ester.
le the functional group in each structural
‘ila.
ime each compound.
C
3
_
_
2
C
O
C
H
F
H
l
Draw the structural formula for the product of the
following condensation reaction:
0
o
.
i
0
0
al C—C
3
O
—CH
h ,iudents should circle the OH, COOl!, and COO in
th respective formulas.
PropallOl, propanoic acid, methyl ethanoate (or
nhanoiC acid methyl ester)
o
C—O +
C
C
Acetic acid, 3
OO
H
H, and butyric acid,
C
c
2
)
0
ll
0
(1
C
1
ll
, are common reactants in condensa
tion reactions. Their structural formulas are shown
below. Predict the products of a condensation reaction
between each acid and each of the following alcohols
by providing the name and structural formula for the
product:
(C
O
a. methanol 3
H
H
)
(C
O
b. ethanol 9
H
,l)
l
(C
O
7
H
c. propanol 3
H).
0
0
3l C—Oil
C
CC
—
Cll 2
H
11 C— OH
Acetic acid
Butyric acid
-
it
What does the R stand for in Roll?
is the rest of the molecule without the functional
OH
C—OH
For example, the product of a condensation reaction
between acetic acid and ethanol is ethyl acetate.
pnup.
Why is the word condensation1 used to describe the
wtiofl that forms esters?
Inc H from the alcohol and the OH from the acid
it ict to form water or condensatio
n.
Condensation
Reactants
Acetic Acid
C
C
3
OH
OH
(EthanoiC Acid)
-r
ButyriC Acid
(ButanOic 1
Acid)
CH
O
Methyla. 3
acetate,
Methyl butyrate,
(rneth
ano$_
E9!-_2
OH
5
H
2
b. C
Ethyl acetate,
Ethyl butyrate, I
(ethanol)
CH COOC 2
H 4 I C 37
H COOC 2
H
_
-
-
-
-
_
_
_
_
OH
7
H
3
c. C
pnoD
I
L
Propyl acetate,
CH3CO0Ct
-
- --
_
Propyl butyrate,
C3H7CO0Ct
Section SummarY
233
I