Chapter 9 Polymers PRE-U STPM CHEMISTRY I SEMESTER 3

Section A: Objective Questions

1. Chloroethene, CH, CHCI, is the monomer of PVC. What are the C-CC bond angles along the
polymeric chain in PVC?
A. They are all 109°
B. Half are 109° and half are 120°C.
C. They are all 120°
D. They are all 180°

2. A substance commonly found in the house or garden has the following properties.
 It is combustible.
 It is an electrical insulator.
 It melts over a range of temperature.

What could the substance be?

A. Brass
B. paper
C. silicon(IV) oxide
D. poly(ethene)

3. In many countries plastic waste is collected separately and sorted. Some of this is incinerated to
preheat for power stations. Why is pvc, polyvinylchloride, removed from any waste that is to be
incinerated
A. It can be melted down and re-used.
B. Its combustion products are harmful.
C. It destroys the ozone layer.
D. It does not burn easily.

4. Which equation or statement describes what happens when poly(propene) is burned in excess of
air?
A. (C3 H6 ) + 3/2 n O₂  3nC +3n H₂O
B. (C3 H6 + 9/2n0₂ 3nC +3n H₂O
C. (C3 H6 + 6 n0₂ 3nC +3n H₂O
D. (Poly(propene) does not burn.
5. The following diagram represents the structure of a possible polymer.

By which method might this polymer be made?

A. polymerise ethene followed by hydration
B. polymerise ethene followed by oxidation with cold acidified KMnO4
C. polymerise 1,2-dichloroethene followed by hydrolysis
D. polymerise 1,2-dichloroethene followed by oxidation with cold acidified KMnO 4

6. Which of the following statements about natural rubber is not true?

A. Its monomer is 2-methyl-1,3-butadiene.
B. It is the trans-isomer of polyisoprene.
C. It can be synthesised by the addition polymerisation of isoprene.
D. It is a saturated hydrocarbon.

7. Polymerisation of 1,1-dichloroethene produces a dense, high melting point substance that does
not allow gases to pass through. It is used as cling wrapping. Which sequence appears in a short
length of the polymer chain?
A. -CH2CCl2CH2CCl2CH2CCl2—
B. CHCICHCICHCICHCICHCICHCl-
C. -CCl2 CCl2 CCl2 CCl2CCl2 CCl2--
D. CHCICHCICHCICHCICCI₂CH₂

8. One of the characteristics of addition polymerisation is that the empirical formulae of the polymer
and of its monomer are the same. The absorbent material in babies' disposable nappies is made
from the addition polymer shown

From which monomer could this addition polymer be obtained?

A. CH3 CH(OH)CO₂H
B. HOCH2CH2CO₂H
C. H₂C=CHCO₂H
D. HO₂CCH=CHCO₂H

9. Textiles for use in aircraft are treated with a finish containing a haloalkane. What is the reason for
this?
I. The fabric forms hydrogen bonds to water more readily, making the fabric easier to wash.
II. The haloalkane undergoes addition polymerisation, stiffening the fabric
III. The textile burns less easily, improving safety.
A. I and III only correct
B. II and IV only correct
C. III and IV only correct
D. I, II and III only correct
10. Which one of the following formulae represents a condensation polymer?

11. In 1933, Gibson and Fawcett maintained ethene at a temperature of 170 °C under a pressure of
200 atm in the presence of a trace of oxygen for several days. What was the principal product
discovered in the reaction vessel when it was cooled and opened?
A. artificial diamonds
B. benzene
C. methane
D. polyethene

12. A polymer has the following repeat unit.

----CH2-CHCI-CH2-CH=CH-CH₂----

Which pair of monomers could be used to make this polymer?

A. CH2=CHCI and CH2=CH2

B. CH2=CHCI and CH2=CH-CH= CH2
C. CH3CH2Cl and CH3-CH=CH-CH3
D. CH2=CCI-CH-CH, and CH2= CH2

13. Which of the following is a repeat unit in a condensation polymer?

A. --- CH2CHCI-
B. ----CH2CH2CH2O----
C. ----OCH CHOCOCH.CO
D. ---OCH2CH2O----

14. 'Superglue' contains the compound

It is rapidly polymerised by traces of bases on the surface of the objects to be stuck together. Which of

the following represents the repeat unit of the polymerised form?

15. Nylon-6,6 has the following formula and undergoes alkaline hydrolysis.

What is the product of the alkaline hydrolysis of Nylon-6,6?

I. HOCH2(CH2)4COONa
II. NH2(CH2)6NH2
III. NaOOC(CH2)4COONa
IV. H3N(CH2)5COOH
A. I and II only correct
B. II and IIII only correct
C. III and IV only correct
D. I, II and III only correct

16. When one mole of compound X is heated with a concentrated solution of potassium
manganate(VII), two moles of compound Y with the molecular formula C2H4O2 is produced.
Compound X undergoes polymerisation in the presence of Al(CH3)3 and TiCl3 to form compound Z.
The structure of Z could be

A. C

B. D
 17. A transparent synthetic polymer is used as packaging material. Its monomer is a polymer could be
hydrocarbon. The
A. Nylon 6,6
B. Terylene
C. Polyvinyl cloride
D. Poly(styrene)

18. Which of the following polymers contains peptide linkages?

A. Poly(propenamide)
B. Natural Rubber
C. Poly(phenylethene)
D. Silk

19. The repeating units of polymers X and Y are as follows:

What is the type of polymerisation occur in X and Y?

A. B. C. D.
X Additional Condensation Additional Condensation
polymerisation polymerisation polymerisation polymerisation
Y Condensation Additional Additional Condensation
polymerisation polymerisation polymerisation polymerisation

20. Which of the following compounds can react with to produce a polymer
with high relative molecular mass?
A. CIOC— COCI

B. HOCH2CH2CH2CH2CH3
C. CH3CH(OH)CH2COOH
D. HOCH2CH2CH2OH

21. Which of the following compounds can act as a monomer in an addition polymerisation process?
A. HOCH2CH2COOH
B. CH3CH2CH2NH2
C. CH3CH=CH2
D. NH2CH2CH2COCI

22. Nylon-6,6 is a condensation polymer derived from hexane-1,6-diamine, H₂N(CH2)6NH2 and

hexanedioic acid, HOOC-C4H8-COOH. Which of the following, reacting with the diamine, would
produce the most rapid method of preparing the polymer?
A. Diethyl hexanedioate
B. Hexane-1,6-diol
C. Hexanedioic acid
D. Hexanedioyl chloride
23. Which of the following pairs of monomers could undergo condensation polymerisation?
A. HOCH2CH2OH and H₂NCH₂CH₂NH₂
B. HOOCCH2CH2COOH and HOCH₂CH₂OH
C. HOOCCH=CHCOOH and CH2=CHCH=CH2
D. HOOCCH2CH2COOH and H₂NCOCH2CH2CONH₂

24. The repeating unit of a polymer is shown below of the following statements is not true of the
polymer?

A. It is elastic.
B. It is thermally stable
C. It can be vulcanised.
D. Its monomers are C,H,CH=CH, & CH2=C(CH)CH=CH2.

25. A Ziegler-Natta catalyst is used to produce high density polyethene because the titanium(IV) ion in
the catalyst
A. has empty d orbital
B. has a low activation energy
C. has many valence electrons
D. can change its oxidation states

26. The repeating unit of a synthetic polymer is shown below

Which statement about the polymer is true?

A. It is a homopolymer.
B. Its monomer is CH2=C(CH3)2
C. It is stable against oxidation.
D. It is waterproof.

27. Plastic can be classified as thermoplastic and thermosetting plastic based on its thermal
properties. Which is a thermosetting plastic?
A. Bakelite
B. Perspex
C. Polystyrene
D. Polyvinyl chloride

28. Ziegler-Natta catalyst is used in addition polymerisation of ethene. Which statement

not true of the process?
 A. It requires a low pressure.
B. It requires a low temperature.
C. It produces high density poly(ethene).
D. It is an example of free radical polymerisation.

29. Teflon, [CF CF2], is a polymer which is used to coat cooking utensils. Which statement about
Teflon is true?
A. It is brittle.
B. It is chemically inert.
C. It is thermally unstable.
D. Its softening temperature is low.

30. Part of the structural formula of a polymer is shown below.

Which statement is true of the polymer?

A. Its monomer is optically active.

B. Its monomer is NH2(CH2) CONH2.
C. Its monomer dissolves in water.
D. Its monomer has a low melting point.

Section B

1. Chloroethene C, is the monomer from which the polymer PVC is produced.

C CH2CH—Cl

C can be obtained from ethene in the laboratory by the following route

Ethene  dichloroethane 

Stage 1 Stage 2

(a) Suggest reagents and conditions for stages I and 11.

(b) Describe the steps in the mechanism of stage 1.
(c) Draw the displayed formula of the PVC chain, showing two repeat units. Of what type of
polymerisation is this an example?

Type of polymerization

Repeating unit:

2. The commercial plastic ABS is rigid and tough. It is used to make suitcases and car body panels. It
is made from three monomers, known in industry as Acrylonitrile, Butadiene and Styrene.
 CH=CH-CN CH=CH-CH=CH₂ C6H3CH=CH2

Acrylonitrile Butadiene Styrene

(a) Assuming that the monomers join together in a 1:1:1 ratio, suggest a repeat unit for ABS.
(b) State the type of polymerisation to form ABS?
(c) The repeat unit still contains a double bond.

(i) Suggest why this could help make ABS the rigid plastic it is.

(ii) Using the repeating unit in (a) show how two chain of ABS can increase the rigidity of the polymer

as stated in (c)(i)

(d) State another polymer that is also used as part of car body panel

3. Hydrophilic polymers find important uses in the manufacture of contact lenses and wound
dressings. Their chemical structures allow them to bond with water molecules, which keeps them
soft and flexible

(a) What type of polymerisation has produced

(i) polymer H:

(ii) polymer J:

(b) What type of attractions occur between these polymers and molecules of water?

(c) Chains of polymer H can be 'cross-linked', i.e. joined together, by reaction with a small bifunctional

molecule.

(i) Which one of the following molecules would be most suitable for such cross linking?

(ii) What type of bond would be formed during the cross-linking?

(d) (i) Suggest reagents and conditions for alkaline hydrolyse polymer J into its monomers.

(ii) Draw the structural formulae of the two products of this hydrolysis reaction.

4. The formula of part of the chain of a synthetic polyamide A is shown below.

 (a) Identify the repeat unit of the polymer by drawing square brackets around it on the above
formula.[1]
(b) Draw the structures of the two monomers from which the polymer could be made.
(c) Another synthetic polymer B, is also formed that has almost the same structure as polyamide
above. The structure of the synthetic polymer is shown below/

I. State the commercial name of polymer B

II. Name the two monomer use to form polymer B
III. State one use and its application in our daily life

5. A polymer can be classified as thermosetting, thermoplastic, and elastomer.

I. What do you understand by the term thermosetting
II. Give an example of a thermosetting polymer

(b) Natural rubber is a type of elastomer.

i. What do you understand by the term elastomer?

(ii) Draw the structure of a monomer and a repeating unit of natural rubber.

c. A synthetic rubber which consists of a mixture of geometrical isomers of poly(buta-1,3-diene) is

sticky and rather useless. What is the name of the catalyst used to prepare a flexible synthetic rubber

d. SBR is a type of synthetic rubber which is gaining importance in the automobile industry. State the

name of monomers which are used to produce SBR.

6. Complete the table below by stating the type of polymerisation and the monomer(s) that are
required to

Polymers Type of Monomer

polymerisation
PRE-U STPM CHEMISTRY I SEMESTER 31 Polymers Chapter 9

Section C :

Essay Questions

1 (a) Using suitable examples, state the differences between additional and condensation polymerisation

(b) Explain the difference between polyethene formed via free radical mechanism and polyethene formed
via Ziegler-Natta catalyst.

2. (a) Nylon 6,6 is commonly used as fabric and also as artificial carpet. State the type of polymerisation
applied in synthesising Nylon 6,6 and name the monomers required to prepare Nylon 6,6

(b) Using 1,4-dichlorobutane as starting material, propose a reaction scheme to synthesis Nylon 6,6

(c) State two other uses of nylon 6,6 and the properties that suits to its application
3 (a) Poly(methyl a-cyanoacrylate) and natural rubber are an example of a thermoplastic and elastomer
used to make "super glue". Part of its structural formulae are shown below.

Draw and name the structural formula of the monomer of poly(methyl a-cyanoacrylate) and natural
rubber

(b) Name the type of polymerisation involved in both poly(methyl a-cyanoacrylate) and natural rubber

(c) Explain why poly(methyl a-cyanoacrylate) is a thermoplastic while natural rubber is elastomer? [2]

(d)Explain how poly(methyl a-cyanoacrylate) can act as adhesive especially when exposed to humid

industrial environment.

(e) By using the molecular structures of natural rubber, suggest a method of how natural rubber can

increase its elasticity

4. (a) In recent years there has been a lot of interest in polymers in the form of gels that absorb aqueous

materials. One of the largest uses of these polymers is in disposable nappies (diapers). The gel which

is used in this case is a polymer of propenoic acid

(i)Draw the polymer formed by propenoic acid with two repeating unit, and state the type of
polymerisation involved

(ii) Explain how the polymer formed by propenoic acid can hold the water that poured in the diapers

(iii) Suggest a property the polymer should have in order to be used in disposable products.

(b)In recent years there has been considerable interest in a range of polymers known as 'hydrogels

the structure of a hydrogel

The hydrogel is formed from chains of one polymer which are cross-linked using another molecule,

(i) Draw the structure of the monomer used in the polymer chains and hence draw the structure of the

molecule used to cross-link the polymer chains. Compare the differences between the

polymerisation used to form the polymer chain and the polymerisation used to cross-link the two

polymer chain.

(ii) Once a hydrogel has absorbed water, it can be dried and re-used many times. Explain why this is

possible, referring to the structure of the polymer