Q1.          In 1939 a scientist opened the valve on a new cylinder of tetrafluoroethene gas. No gas came out.

He cut the cylinder open and found that the gas had changed into a white solid. This solid was an addition polymer.

(a)     Give the name of the addition polymer that formed inside the cylinder.

........................................................................................................................ (1)

(b)     The structure of this polymer can be represented by the diagram below.

Draw the structure of the monomer, tetrafluoroethene, from which it is formed.

 

 

 

 

 

  (2)

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(c)     Describe how this addition polymer forms from monomers.

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(Total 6 marks)

   

Q2.         This question is about the use hydrocarbons and the production of compounds from hydrocarbons.

(a)     The equation shows a reaction involving hydrocarbons.

                 C8H

18                →                C

2H

4                 +                C

6H

14

        Hydrocarbon J                     Hydrocarbon K                    Hydrocarbon L

Choose the correct processes from the box to complete the sentences.  

combustion       hydration        thermal decomposition        polymerisation

(i)      Hydrocarbons K and L are produced by ........................................... . (1)

(ii)     Ethanol can be produced from hydrocarbon K by .............................. . (1)

(iii)     Describe a test to distinguish between hydrocarbons K and L and give the result of the test.

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............................................................................................................... (2)

(b)     Hydrocarbon J burns completely in oxygen to produce carbon dioxide and water vapour.

2 C8H

18        +         25 O

2         →          16 CO

2         +        18 H

2O

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(i)      When 114g of hydrocarbon J burns completely in 400g of oxygen it produces 162g of water vapour.

What mass of carbon dioxide would be produced from burning 114g of hydrocarbon J?

Show clearly how you work out your answer

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Answer = ................................. g (2)

(ii)     The mass of carbon dioxide produced is greater than the 114g of hydrocarbon J that was burned. Explain why.

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............................................................................................................... (2)

(c)     Two different processes are used to produce ethanol.  

Process 1   Process 2

Fermentation of a sugar solution by yeast in a reaction vessel.

 

The reaction vessel has to be emptied, cleaned and refilled every few days.

 

The process produces a 15% ethanol solution in water.

Reaction of ethene (from crude oil) with steam in a reactor.

 

The reaction is only stopped if there is a fault in the reactor.

 

The process produces 100% ethanol.

(i)      Give one advantage that Process 1 has over Process 2.

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............................................................................................................... (1)

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(ii)     What advantages to a manufacturer of ethanol, does Process 2 have over Process 1?

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(Total 11 marks)

   

Q3.          (a)     PEX is a material that is used as an alternative to copper for hot water pipes. PEX is made from poly(ethene).

(i)      Describe how ethene forms poly(ethene).

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........................................................................................................................... (2)

(ii)     PEX is a shape memory polymer. What property does a shape memory polymer have?

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........................................................................................................................... (1)

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(iii)     The simplified structures of poly(ethene) and PEX are shown.

                Poly(ethene)                                                                     PEX

         Poly(ethene) is a thermoplastic that softens easily when heated.

         Suggest and explain how the structure of PEX changes this property.

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(b)     Copper was considered to be the most suitable material to use for hot water pipes. PEX is now used as an alternative material for hot water pipes.

          Copper is extracted from its ore by a series of processes. 1   The low-grade ore is powdered and concentrated. 2   Smelting is carried out in an oxygen flash furnace. This furnace is heated to 1100 °C

using a hydrocarbon fuel. The copper ore is blown into the furnace with air, producing impure, molten copper.

3   Oxygen is blown into the impure, molten copper to remove any sulfur. The copper is cast into rectangular slabs.

4   The final purification of copper is done by electrolysis.

          PEX is made from crude oil by a series of processes. 1   Fractional distillation 2   Cracking 3   Polymerisation 4   Conversion of poly(ethene) into PEX

          Suggest the possible environmental advantages of using PEX instead of copper for hot water pipes.

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(Total 10 marks)

 

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          Modem window frames are often made from uPVC which contains the plastic poly(chloroethene).

Replace your old wooden windows with our super high quality uPVC

windows!

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(a)     State why plastic window frames need no painting or maintenance.

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(b)     Poly(chloroethene) is a polymer formed by the addition polymerisation of chloroethene.

(i)      Chloroethene is an unsaturated molecule. Why is this molecule said to be unsaturated?

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(ii)     Complete the diagram to represent how poly(chloroethene) is formed from chloroethene.

(3)

(iii)     Explain what is meant by the term polymerisation.

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(iv)    Why is this an addition polymerisation?

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(Total 8 marks)

   

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Q5.          (a)     Alkenes can be made by cracking large alkane molecules.

(i)      Explain how the cracking process is carried out.

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.......................................................................................................................... (2)

(ii)     Give a chemical test which would show the difference between an alkene and an alkane.

Test ..................................................................................................................

Result of test ....................................................................................................

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(b)     Alkenes, such as ethene, can be made into polymers.

(i)      Complete the following to show how the ethene molecules bond to form part of a polymer.

 

 

 

 

 

  (1)

(ii)     Name the polymer formed from ethene.

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(iii)     Explain one important problem caused by the everyday use of this polymer.

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(Total 8 marks)

 

Q6.          One reason the oil industry is important is that it uses crude oil to produce many of the plastic materials we use in everyday life.

          (a)     The first stage in the formation of a plastic material is called cracking. Butane (C4H

10), a

hydrocarbon in crude oil, can be cracked to produce two different hydrocarbons, ethane (C

2.4) and ethene (C

2H

4)

(i)      For cracking to happen what needs to be done to the hydrocarbon?

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........................................................................................................................... (2)

(ii)     Complete the equation for the cracking of butane using displayed formulae.

(2)

(iii)     Complete the balanced chemical equation far the complete combustion of ethane in oxygen.

............C2.4(g)  +  ............(g)  →  ............(g)  +  ............(l)

(3)

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(b)     The second stage is the formation of the plastic material by polymerisation.

          Describe how ethene (C2H

4) forms poly(ethene). You do not need to give the reaction

conditions or the names of catalysts.

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(Total 10 marks)

 

Q7.          Propane and ethene are both important hydrocarbons.

(a)     Complete the table by adding the formula of the ethene molecule and the structure of the propane molecule.

(2)

(c)     Ethene can be changed into a plastic. The equation shown below represents the reaction in which ethene is polymerised.

(i)      What is the name of the plastic formed in this reaction?

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(ii)     What type of polymerisation reaction is shown in the equation?

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(Total 4 marks)

 

Q8.          The label has been taken from a tube of Humbrol Polystyrene Cement, a glue used in model making.

(a)     The solvent used is 1,1,1-trichloroethane. The structural formula of this molecule is:

(i)      What do the lines between the atoms represent?

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(ii)     State whether 1,1,1-trichloroethane is saturated or unsaturated. Give one reason for your answer.

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(iii)     1,1,1-trichloroethane is being replaced in favour of a ‘better’ solvent. Use information on the label to help you to suggest why.

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(b)     Polystyrene is a plastic. Plastics are polymers which are made by the process of polymerisation.

(i)      What is meant by polymerisation?

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........................................................................................................................... (2)

(ii)     The table gives information about monomers and the polymers made from them. Complete the table.

(3)

(Total 8 marks)

   

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Q9.          The many hydrocarbons in crude oil are separated into fractions.

(a)     Some of the larger hydrocarbon molecules can be broken down to produce smaller, more useful hydrocarbon molecules.

          Hexane and butane are alkanes. Describe the structure of alkanes.

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(b)     Ethene is used to make poly(ethene).

          This process is called polymerisation. Explain what is meant by polymerisation.

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(Total 5 marks)

 

Q10.          The diagram shows a reaction which takes place in an oil refinery.

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(a)     X, Y and Z are all examples of which type of compound?

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(b)     What type of chemical reaction takes place when compound X is converted into compounds Y and Z?

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(c)     Compounds Y and Z are both useful substances.

          Compound Y is unsaturated. Compound Z is saturated.

(i)      Suggest one use for compound Y.

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(ii)     Suggest one use for compound Z.

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(Total 4 marks)

 

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M1.          (a)     polytetrafluoroethene 1

(b)

4 single bonds C-F

1

1 double bond C=C 1

(c)     many tetrafluoroethene monomers / molecules 1

join / bond together accept higher level answer relating to ‘double bond opening’

1

to form a very large molecule / chain 1

[6]

   

M2.         (a)     (i)      thermal decomposition 1

(ii)      hydration 1

(iii)      add bromine (water)/iodine solution (to K and L) 1

K will decolourise these solutions or L will not decolourise these solutions

1

(b)     (i)      352 (g) for correct answer if answer is incorrect 400 + 114 – 162 gains 1 mark

2

(ii)     because 2 molecules of hydrocarbon J had 25 molecules of oxygen added

or

because 2 molecules of hydrocarbon J produced 16 molecules of carbon dioxide

allow because oxygen has been added to hydrocarbon J for 1 mark

2

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(c)     (i)      raw materials are renewable accept does not use crude oil

1

(ii)     alcohol does not need to be distilled accept alcohol produced is pure

1

process is continuous 1

[11]

   

M3.          (a)     (i)      many ethene / molecules / monomers

accept double bonds open / break 1

         join to form a long hydrocarbon / chain / large molecule accept addition polymerisation ignore references to ethane correct equation gains 2 marks

1

(ii)     (can be deformed but) return to their original shape (when heated or cooled)

ignore ‘it remembers its shape’ 1

(iii)     cross links / extra bonds in PEX accept inter-molecular bonds ignore inter-molecular forces

1

         molecules / chains in PEX are held in position accept rigid structure

1

         molecules / chains in PEX unable to slide past each other / move it = PEX throughout

1

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(b)     any four from:

•        less (hydrocarbon) fuels used allow less energy

•        less / no electrical energy used allow no electrolysis

•        reduce carbon / carbon dioxide emissions allow less global warming

•        reduce / no pollution by sulfur dioxide / acid rain

•        continuous process allow less / no transportation

•        conserve copper which is running out or only low-grade ores available

•        reduce the amount of solid waste rock that needs to be disposed allow less waste

•        reduce the need to dig large holes (to extract copper ores) allow less mining ignore costs / sustainability / non-renewable

4 [10]

 

M4.          (a)     not broken down by microorganisms or not bio-degradable

accept alternative answers such as: do not rot / corrode / fade / react with atmosphere etc any answers which imply the inertness or non-biodegradability of this plastic accept they don’t react, they are ‘inert’ ignore rusting do not accept weathering

1

(b)     (i)      (have a) double bond or do not have maximum number of (hydrogen) atoms attached

accept can add / react with hydrogen accept can take part addition reactions do not accept it is a double bond do not accept additional reactions do not accept has ‘spare’ / ‘free’ bond do not accept alkene alone

1

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(ii)     single bond between carbon atoms 1

         all atoms correct + 2 ‘linking’ bonds (linking bonds need not go through bracket)

1

         n moved to bottom right of bracket i.e. is below  way on the right first 2 marks are possible for chain structures accept [– CHCl–CH

2–]

n

1

(iii)     many molecules or many monomers 1

         joined / bonded / linked or form long chain molecules / large molecules or to form a long chain polymer

accept many alkenes or many (ethene) molecules do not accept many ethene alone etc.

to form a long polymer is not enough for 2nd mark

1

(iv)    no other substances formed (A + B → C)

allow because double bond breaks so other atoms can add allow one product only do not accept saturation occurs

1 [8]

 

M5.          (a)     (i)      by heating

pressure is neutral

using a catalyst/pot/ceramic/porcelain/aluminium oxide 1

(ii)     use bromine water/(alkaline) permanganate accept bromine

1

alkene makes bromine go colourless or lose its colour accept alkane does not change the red/orange colour of bromine not change colour/goes clear

1

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(b)     (i)      either of these must show bonds at end

1

or

not H on ends allow 3 instead of n not any other number

(ii)     poly(ethene) – brackets not essential accept polythene

1

(iii)     large amount of waste polymer/poly(ethene)/polythene/litter

accept large amount of crude oil or finite resource used 1

it is not biodegradable accept it does not decompose/decay/break down it causes pollution/it creates toxic fumes when burnt are neutral not it is not recyclable

2 [8]

 

M6.          (a)     (i)      heat

accept increase temperature ignore pressure 1

with a catalyst 1

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(ii)     1

        

accept displayed formulae only

1

(iii)     O2

1

CO2 + H

2O

ignore state symbols 1

         correct balancing 2 + 7 → 4 + 6

accept 1 + 3 → 2 + 3 only if reactants and products correct 1

(b)     double bond breaks 1

many (ethene) molecules

accept many monomers 1

bond together accept join or combine for bond accept

 

for first 2 marks ignore unsaturated becomes saturated 1

[10]

 

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M7.          (a)     C2H

4

1

             H H H H C C C H    H H H

Accept even if in wrong columns 1

(c)     (i)      polythene or poly(ethene) 1

(ii)     addition 1

[4]

 

M8.          (a)     (i)      bonds / pair of electrons / shared electrons

for one mark 1

(ii)     saturated since it has single bonds / no double bonds / no multiple bonds / maximum number of atoms attached

for one mark 1

(iii)     sensible answer (e.g. it is harmful) or better solvent could be used on expanded polystyrene or foam

for one mark 1

(b)     (i)      simply writing monomers form / react to form polymers gains no mark monomers join / bond / combine / link to form polymers = 1 mark the mark is for the idea of joining to gain the second mark the idea of the relative size of monomer and polymer is required small molecules join to form a polymer (2 marks) many monomers join to form a polymer (2 marks) monomers join to form a large molecule / long chain (2 marks) many molecules join together (2 marks)

for 1 mark each 2

(ii)     polyethene / poly(ethene) / polythene

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         don’t worry too much about the exact positioning of the C6H

5 at

the end of the bond

         placement of linking bonds inside / outside brackets is not important must have n

for 1 mark each 3

[8]

 

M9.          (a)     any three from

          carbon (atom) spine / chain accept idea of ‘backbone’ of carbon (atoms)

          surrounded by hydrogen (atoms) accept idea of only bonded to hydrogen (atoms)

3

          single (covalent) bonds between carbon atoms accept no double bonds

          saturated (hydrocarbons)

          (general formula) CnH

2n+2

(b)     many small molecules/ monomers accept many unsaturated molecules or alkenes

1

          join together to form a large / long molecule / polymer 1

[5]

 

M10.          (a)     hydrocarbon 1

(b)     thermal decomposition / cracking 1

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(c)     (i)      making polymers / poly(e)thene accept plastic (bags)

1

(ii)     fuel 1

[4]

 

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