Polymers (Cambridge (CIE) IGCSE Co-ordinated Sciences (Double Award): Chemistry): Exam Questions

Extended tier only

Alkenes are unsaturated hydrocarbons. They show structural isomerism. Alkenes take part in addition reactions and form polymers.

Ethene reacts with each of the following. Give the name and structural formula of each product.

i) steam

 name of product ..........................................................

 structure of product

[2]

ii) hydrogen 

name of product ........................................................... 

structure of product 

[2]

Extended tier only

Islay is an island off the west coast of Scotland. The main industry on the island is making ethanol from barley.

Barley contains the complex carbohydrate, starch. Enzymes catalyse the hydrolysis of starch to a solution of glucose.

Alkenes polymerise by addition.

i) Explain the term polymerise. 

[2]

ii) What is the difference between addition polymerisation and condensation polymerisation? 

[2]

iii) Poly(dichloroethene) is used extensively to package food. Draw its structure. The structural formula of dichloroethene is drawn below.  

[2]

Extended tier only

The structure of PLA is given below.

i) What type of compound contains the group that is circled?

[1]

ii) Complete the following sentence. Lactic acid molecules can form this group because they contain both an ............................. group and an ............................. group.

[2]

iii) Is the formation of PLA, an addition or condensation polymerisation? Give a reason for your choice.

[2]

When lactic acid is heated, acrylic acid is formed.

i) Complete the word equation for the action of heat on lactic acid.

lactic acid → ..................................... + ..................................... 

[1]

ii) Describe a test that would distinguish between lactic acid and acrylic acid.

test ..........................................................................................................

result for lactic acid ..........................................................................................................

result for acrylic acid ..........................................................................................................

[3]

iii) Describe a test, other than using an indicator, which would show that both chemicals contain an acid group.

test ..........................................................................................................result ..........................................................................................................

[2]

Extended tier only

State two uses of synthetic polymers.

Extended tier only

The structural formulae of two synthetic polymers are given below. 

i) Draw the structural formula of the monomer of polymer A. 

[2]

ii) Identify the functional group circled in polymer B. 

[1]

iii) Deduce the two types of organic compound which have reacted to form polymer B. 

[2]

Extended tier only

Explain the difference between addition and condensation polymers. Classify A and B as either addition or condensation polymers.

Extended tier only

Polymers are made by the polymerisation of simple molecules called monomers.

i) The structural formula of a polymer is given below.

 This polymer is made by addition polymerisation. Draw the structural formula of its monomer. 

[1]

 ii) The two monomers shown below form a nylon which is a condensation polymer.

 Draw its structural formula showing one repeat unit of the polymer.

[3]

iii) Name the natural macromolecule which contains the same linkage as nylon.

[1]

iv) Explain the difference between addition polymerisation and condensation polymerisation. 

[2]

Extended tier only

i) Deduce the structural formula of the monomer from that of the polymer.

 structural formula of monomer ..................................................

[1]

ii) Deduce the structural formula of the polymer, poly(phenylethene), from the formula of its monomer, phenylethene.

 structural formula of polymer ..................................................

[2]

Extended tier only

The carbohydrate, glucose, polymerises to form the more complex carbohydrate starch.

If glucose is represented by 

 then the structural formula of starch is as drawn below. 

 How does the polymerisation of glucose differ from that of an alkene such as phenylethene?

Domestic rubbish is disposed of in landfi ll sites. Rubbish could include the following items.

 Explain why aluminium, a reactive metal, takes so long to corrode.

Extended tier only

Both paper and cotton are complex carbohydrates. They can be hydrolysed to simple sugars such as glucose.

The formula of glucose can be represented as: 

Draw the structural formula of a complex carbohydrate, such as cotton.

Include at least two glucose units.

Extended tier only

i) There are two types of polymerisation reaction. Give their names and explain the differences between them. 

[4]

ii) Give the structural formula of a polymer which is formed from two different monomers.  

[2]

Extended tier only

There are two types of polymerisation - addition and condensation.

Explain the difference between them.

Extended tier only

Poly(dichloroethene) is used to package food. Draw its structure. The structural formula of dichloroethene is shown below. 

Extended tier only

Enzymes are biological catalysts. They are used both in research laboratories and in industry.

Enzymes called proteases can hydrolyse proteins to amino acids. The amino acids can be separated and identified by chromatography. The diagram below shows a typical chromatogram.

 i) The R_f value of a sample = 

 Some R_f values for amino acids are: 

• glutamic acid = 0.4

• glycine = 0.5

• alanine = 0.7

• leucine = 0.9

 Identify the two amino acids on the chromatogram.

 A is ..............................    B is .............................. 

[2]

ii) Explain why the chromatogram must be exposed to a locating agent before R_f values can be measured. 

[1]

iii) Measuring R_f values is one way of identifying amino acids on a chromatogram. 

Suggest another. 

[1]

iv) The synthetic polymer, nylon, has the same linkage as proteins. Draw the structural formula of nylon. 

[3]

Fermentation can be carried out in the apparatus drawn below. After a few days the reaction stops. It has produced a 12% aqueous solution of ethanol.

i) Complete the equation.

C₆H₁₂O₆ ..............................
→ + ..............................
glucose ethanol carbon dioxide 

[2]

 ii) Suggest a reason why the reaction stops after a few days. 

[1]

iii) Why is it essential that there is no oxygen in the flask? 

[1]

 iv) What technique is used to concentrate the aqueous ethanol? 

[1]

Extended tier only

Give the name of the product when but-1-ene reacts with each of the following.

steam .........................................................

hydrogen ....................................................

bromine ......................................................

Extended tier only

Ethene reacts with each of the following. Give the name and structural formula of each product.

 i) steam 

name of product .......................................................... 

structure of product .......................................................... 

[2]

ii) hydrogen 

name of product ........................................................... 

structure of product .......................................................... 

[2]

Extended tier only

Alkenes polymerise by addition.

 i) Explain the term polymerise. 

[2]

ii) What is the difference between addition polymerisation and condensation polymerisation? 

[2]

iii) Poly(dichloroethene) is used extensively to package food. Draw its structure. The structural formula of dichloroethene is drawn below.  

[2]

What is meant by the term unsaturated hydrocarbon?

unsaturated ..................................................

hydrocarbon ..................................................

Describe a test that would distinguish between saturated and unsaturated hydrocarbons.

reagent ..................................................

observation (saturated hydrocarbon) ..................................................

observation (unsaturated hydrocarbon) ..................................................

Extended tier only

Addition polymers can be made from alkenes. The diagram shows part of an addition polymer. 

 i) Draw a circle on the diagram to show one repeat unit in this polymer. 

[1]

 ii) Give the structure and the name of the monomer used to make this polymer. 

structure ..................................................  

name .................................................. 

[2]

 iii) Give the structure of an isomer of the alkene in (e)(ii).

[1]

Extended tier only

Alkenes can form polymers.

What type of polymerisation occurs when alkenes form polymers?

Extended Only

Part of the structure of a polymer is shown.

Draw the structure of the alkene from which this polymer can be made. Show all of the atoms and all of the bonds.

Extended tier only

Part of the structure of a polyamide is shown.

This polyamide is formed from identical monomers. Complete the diagram to show the structure of one monomer. Show all of the atoms and all of the bonds.

Extended tier only

There are two types of polymerisation, addition and condensation.

Explain the difference between these two types of polymerisation.

Extended tier only

The polymer known as PVA is used in paints and adhesives. Its structural formula is shown below.

Deduce the structural formula of its monomer.

Extended tier only

A condensation polymer can be made from the following monomers.

HOOC(CH₂)₄COOH and H₂N(CH₂)₆NH₂ 

Draw the structural formula of this polymer.

Extended tier only

A South Korean chemist has discovered a cure for smelly socks. Small particles of silver are attached to a polymer, poly(propene), and this is woven into the socks.

i) Give the structural formula of the monomer.

[1]

ii) Draw the structural formula of the polymer.

[2]

iii) Suggest which one, monomer or polymer, will react with aqueous bromine and why?

[2]

Extended tier only

To show that the polymer contains silver the following test was carried out. 

The polymer fibres were chopped into small pieces and warmed with nitric acid. The silver atoms were oxidised to silver(I) ions. The mixture was filtered. Aqueous sodium chloride was added to the filtrate and a white precipitate formed.

i) Why was the mixture filtered?

[1]

ii) Explain why the change of silver atoms to silver ions is oxidation.

[1]

iii) Give the name of the white precipitate.

[1]

Monomers polymerise to form polymers or macromolecules.

i) Explain the term polymerise. 

[1]

ii) There are two types of polymerisation - addition and condensation. What is the difference between them?

[2]

An important monomer is chloroethene which has the structural formula shown below.

 It is made by the following method. 

C₂H₄ + Cl₂ → C₂H₄Cl₂ dichloromethane

 This is heated to make chloroethene.  

C₂H₄Cl₂ → C₂H₃Cl + HCl

 i) Ethene is made by cracking alkanes. Complete the equation for cracking dodecane. 

C₁₂H₂₆ → .................... + 2C₂H₄ 

[1]

 Another method of making dichloroethane is from ethane. 

C₂H₆ + 2Cl₂ → C₂H₄Cl₂ + 2HCl

ii) Suggest a reason why the method using ethene is preferred. 

[1]

iii) Describe an industrial method of making chlorine.  

[2]

iv) Draw the structural formula of poly(chloroethene). 

Include three monomer units. 

[2]

Extended tier only

Synthetic polymers are widely used in the modern world.

Their use has brought considerable advantages to modern life as well as some disadvantages.

 i) Suggest two advantages of a plastic bucket compared to a steel bucket. 

[2]

ii) Name two uses of man-made fibres, such as nylon and Terylene.  

[2]

 iii) Describe the pollution caused by synthetic polymers.  

[3]

Extended tier only

One type of polymer is formed by addition polymerisation.

i) The structural formula of an addition polymer is given below.

 Give the name and structural formula of the monomer.

 name of monomer .................................................. 

[1]

 structural formula of monomer 

[1]

ii) Draw the structural formula of the addition polymer formed by the polymerisation of phenylethene. The structural formula of phenylethene is given below.

[2]

Extended tier only

Nylon is made by condensation polymerisation. It has the structural formula shown below.

 i) Name the linkage in this polymer. 

[1]

ii) Name the natural macromolecules which have the same linkage. 

[1]

iii) Deduce the formulae of the two monomers which reacted to form the nylon and water. 

monomer .......................................................................................................... 

monomer .......................................................................................................... 

[2]

Cooking products, fats and vegetable oils, are mixtures of saturated and unsaturated esters.

 The degree of unsaturation can be estimated by the following experiment. 4 drops of the oil are dissolved in 5 cm³ of ethanol. Dilute bromine water is added a drop at a time until the brown colour no longer disappears. Enough bromine has been added to the sample to react with all the double bonds.

i) Complete the one blank space in the table. 

[1]

ii) Complete the equation for bromine reacting with a double bond.

[2]

 iii) Using saturated fats in the diet is thought to be a major cause of heart disease.  

Which of the products is the least likely to cause heart disease? 

[1]

Extended tier only

A better way of measuring the degree of unsaturation is to find the iodine number of the unsaturated compound. This is the mass of iodine that reacts with all the double bonds in 100 g of the fat.

Use the following information to calculate the number of double bonds in one molecule of the fat.

Mass of one mole of the fat is 884 g.

One mole of I₂ reacts with one mole C=C.

The iodine number of the fat is 86.2 g.

Complete the following calculation.

100 g of fat reacts with 86.2 g of iodine.

884 g of fat reacts with .............................. g of iodine.

One mole of fat reacts with .............................. moles of iodine molecules.

Number of double bonds in one molecule of fat is ..............................

Extended tier only

Polymers are extensively used in food packaging. Poly(dichloroethene) is used because gases can only diffuse through it very slowly. Polyesters have a high thermal stability and food can be cooked in a polyester bag.

The structure of poly(dichloroethene) is given below.

i) Draw the structural formula of the monomer.

[1]

ii) Explain why oxygen can diffuse faster through the polymer bag than carbon dioxide can.

[2]

Extended tier only

i) A polyester can be formed from the monomers HO-CH₂CH₂-OH and HOOC-C₆H₄-COOH. Draw the structure of this polyester.

[2]

ii) Suggest what is meant by the term thermal stability.

[1]

i) Describe two environmental problems caused by the disposal of plastic (polymer) waste.

[2]

ii) The best way of disposing of plastic waste is recycling to form new plastics. What is another advantage of recycling plastics made from petroleum?

[1]

Alkanes and alkenes are both series of hydrocarbons.

i) Explain the term hydrocarbon. 

[1]

ii) What is the difference between these two series of hydrocarbons?  

[2]

Alkenes and simpler alkanes are made from long-chain alkanes by cracking.

Complete the following equation for the cracking of the alkane C₂₀H₄₂.

C₂₀H₄₂ → 2C₄H₈ + 2C₂H₄ + ...............

Extended tier only

Alkenes such as butene and ethene are more reactive than alkanes.

Alkenes are used in the petrochemical industry to make a range of products, which includes polymers and alcohols.

i) Dibromoethane is used as a pesticide. Complete the equation for its preparation from ethene.

+ Br₂ →    

[1]

 ii) The structural formula of a poly(alkene) is given below.

 Deduce the structural formula of its monomer.

[2]

iii) How is butanol made from butene, CH₃–CH₂–CH=CH₂? Include an equation in your answer.

[2]

 iv) Cracking changes alkanes into alkenes. How could an alkene be converted into an alkane? Include an equation in your answer. 

[2]

Extended tier only

20c m³ of a hydrocarbon was burnt in 175 cm³ of oxygen. After cooling, the volume of the remaining gases was 125 cm³. The addition of aqueous sodium hydroxide removed carbon dioxide leaving 25 cm³ of unreacted oxygen.

i) volume of oxygen used = .......... cm³ 

[1]

ii) volume of carbon dioxide formed = .......... cm³ 

[1]

iii) Deduce the formula of the hydrocarbon and the balanced equation for the reaction. 

[2]

Extended tier only

A polymer has the structure shown below.

 (i) What type of polymer is this? 

[1]

(ii) Complete the following to give the structures of the two monomers from which the above polymer could be made. 

[2]

Petroleum is a source of many important chemicals.

Name two industrial processes which must take place to produce alkenes from petroleum.

Extended tier only

Ethene, CH₂=CH₂, and propene, CH₂=CHCH₃, can both be converted into polymers.

 i) What type of polymerisation takes place when ethene forms a polymer? 

[1]

 ii) What is the empirical formula of the polymer formed from ethene? 

[1]

 iii) Propene has the structural formula CH₂=CHCH₃. 

Draw two repeat units of the polymer made from propene. 

[2]

Extended tier only

Ethene will react with steam to form ethanol.

Propene will react with steam to form two isomers, both of which are alcohols.

Suggest the structures of these alcohols.