CE : Section 6 Products from Petroleum LQ P.1CE : Section 6 Products from Petroleum

1. 93 1(e)(i) The structure of a typical anionic detergent can be represented by :

(1) Using the above represented, draw a diagram to show how the detergent can suspend an oil droplet in water.

(2) A table cloth stained with oil can be cleaned using the detergent in water. Explain the cleaning action with reference to your diagram in (1).

(ii) Scientists have also developed cationic detergents for special cleaning purposes. The structure of a typical cationic detergent is shown below :

Can anionic and cationic detergents be used together ? Explain your answer.(6 marks)

2. 94 3 The following diagrams show some items made of synthetic polymers.

(a) Which of the above items is most likely to be made of thermosetting plastics ? Explain your answer.

(b) Name one synthetic polymer which is suitable for making the plastic bag.(c)* Suggest a suitable moulding method used in making the electric switch.(d) Terylene, a polyester fibre used for making the shirt is synthesized from ethane-1,2-diol,

HOCH2CH2OH and benzene-1,4-dicarboxylic acid, HOOCC6H4COOH.(i) Name the type of polymerization involved in the synthesis of terylene.(ii) Write a repeating unit of terylene.

(6 marks)

3. 94 6(b) The following paragraph was taken from a student's laboratory report :

'A mixture of ethanol, ethanoic acid and several drops of concentrated sulphuric acid was heated under reflux for some time. The resulting mixture was then cooled and poured into a beaker containing some saturated sodium chloride solution.’

(i) Draw a labelled diagram of the experimental set-up used for heating the mixture under reflux.(ii) Why is it necessary

(1) to use concentrated sulphuric acid in the above experiment ?(2) to heat the mixture under reflux ?

(iii) What would be observed when the resulting mixture was poured into the saturated sodium chloride solution?

(7 marks)

4. 95 7(b) The following flow diagram shows the conversion of a compound X to an acid Y.

X can rapidly decolourize a solution of bromine in 1,1,1-trichloroethane.(i) What is X ? Name the industrial process by which X is converted to ethanol.

CE : Section 6 Products from Petroleum LQ P.2(ii) Write a chemical equation for the reaction between X and bromine.(iii) (1) Give the systematic name of Y.

(2) Draw a labelled diagram of the laboratory set-up for the conversion of ethanol to Y.(iv)Ethanol can be detected in the breath of a drunken driver. Suggest ONE chemical test to show

the presence of ethanol in his breath and state the observable change produced by the test.(9 marks)

5. 95 9(a) Sodium hydroxide can be used as a raw material in the manufacture of both soapy and soapless detergents.(i) Briefly describe how a soapy detergent can be prepared from a vegetable oil in a school

laboratory.(ii) The formula of a certain soapy detergent is CnH2n+1COONa and its formula mass is between 300

and 310. Calculate the value of n.(iii) The structure of a certain soapless detergent is shown below :

(1) What other raw materials, apart from sodium hydroxide, are required in the manufacture of this soapless detergent ?

(2) Give ONE advantage and ONE disadvantage of using this soapless detergent for domestic cleaning compared with using a soapy detergent.

(Relative atomic masses : H=1.0, C=12.0, O=16.0, Na=23.0 )(10 marks)

6. 96 7(b) The flow diagram below shows the three key stages involved in the production of polypropene bottles from crude oil.

(i) What is the process involved in obtaining heavy oil from crude oil in Stage I ?(ii) (1) Draw the structure of monomer A.

(2) What are the TWO main processes involved in the production of monomer A from heavy oil in Stage II?

(iii) What are the TWO main processes involved in the production of polypropene bottles from monomer A in Stage III?

(iv)Suggest ONE reason why the disposal of polypropene wastes can cause pollution problems.(v) Polypropene wastes can be recycled by melting and remoulding.

(1) What preliminary treatment of the polypropene wastes is required before recycling?(2) Name ONE plastic which cannot be recycled by melting and remoulding.

(9 marks)

7. 97 1(c) For the task listed in the table below, decide which substance on the right is the best to use to accomplish the task. Explain your answer in each case.

(3 marks)

8. 97 7(b) The structures of five compounds, I, II, III, IV and V, are shown below:

CE : Section 6 Products from Petroleum LQ P.3

(i) Which compound can be used to make an addition polymer? Write a chemical equation to represent the addition polymerization.

(ii) Which TWO compounds can be used to make a condensation polymer? Draw the repeating unit of the polymer formed.

(iii) Upon heating with sodium hydroxide solution, one of these compounds produces a soapy detergent.(1) What is this compound?(2) Draw the structure of the soapy detergent produced.(3) Briefly explain the emulsifying action of the detergent when it is used to remove greasy dirt.

(10 marks)

9. 98 2(a) For each of the following experiments, state the expected observation and write a relevant chemical equation.(a) Ethene is passed into an acidified potassium permanganate solution.(b) A mixture of butane and bromine vapour is exposed to diffused sunlight.(c) A sodium sulphite solution is added to an iodine solution (iodine dissolved in aqueous

potassium iodide).(6 marks)

10. 98 6(b) The table below includes some information about three types of dry cells. The voltage of each type of cell is 1.5 V.

Type Voltage over discharge

Price per cell / $ Shelf life / years Life / minutes

Zinc-carbon cell (AA size)

falls quite rapidly 2.5 1.5 70

Alkaline manganese cell (AA size) remains steady 5.0 3 90Silver oxide cell (button type) remains steady 8.0 2 30

(The life of a cell has been determined from its use in a test with a motorized toy.)(i) Decide and explain which type of cell should be used in a small CD-player (Discman).(ii) A package of 24 zinc-carbon cells is now being offered at a special price of $49.90. Assuming

that your radio consumes one zinc-carbon cell per month, would you buy a package of these specially-priced cells for the use of your radio? Explain your answer.

(iii) The half-equations below show the changes at the two electrodes, A and B, of a silver oxide cell during discharge:

A: Zn(s) + 2OH-(aq) ZnO(s0 + H2O(l) + 2e-

B: Ag2O(s) + H2O(l) + 2e- 2Ag(s) + 2OH-(aq)(1) Decide and explain which electrode, A or B, is the anode.(2) Write the overall equation for the reaction that would occur in the cell during discharge.

(iv)The following information was found on the packaging of a brand of zinc-carbon cells:

Caution : 1. Do not dispose of used cells in fire.2. Remove cells when not in use for prolonged periods.

(1) Explain why used cells should not be disposed of in fire.(2) Explain why the cells should be removed when not in use for prolonged periods.

CE : Section 6 Products from Petroleum LQ P.4(9 marks)

11. 98 7(b) Polyvinyl chloride (PVC) is a plastic which has a wide range of uses.(i) Write the chemical equation for the formation of PVC from its monomers.(ii) Plastic products made of PVC may vary greatly in rigidity.

(1) Give ONE flexible product made of PVC.(2) Give ONE rigid product made of PVC.(3) Explain whether PVC is suitable for making electric sockets or not.

(iii) Incineration of PVC wastes produces hydrogen chloride which causes air pollution.(1) State ONE harmful effect of the discharge of hydrogen chloride into the atmosphere.(2) Suggest how hydrogen chloride can be removed from incinerator flue gas prior to its

discharge to the atmosphere.(3) Suppose that all the chlorine in PVC is converted to hydrogen chloride upon incineration.

Calculate the volume of hydrogen chloride produced, measured at room temperature and pressure, when a plastic waste containing 1000 kg of PVC is incinerated.

(Relative atomic masses : H = 1.0, C = 12.0, Cl = 35.5; molar volume of gas at room temperature and pressure = 24.0 dm3)

(9 marks)

12. 98 9(a) A student used the following set-up to prepare propanoic acid:

(i) Name apparatus X.(ii) Explain why some pumice stones were added to the reaction mixture before heating.(iii) Write the chemical equation for the reaction involved.(iv)Suggest a method to obtain propanoic acid from a reaction mixture.The student used to propanoic acid obtained to carry out the following experiment:

(v) Why is a water bath, instead of a naked flame, used for heating the test tube and its contents?(vi) (1) State TWO observable changes when the contents of the test tube were added to the

sodium carbonate solution.(2) Give the systematic name of the carbon compound formed in the experiment.

(8 marks)

13. 99 1 Each of the tasks listed in the table below can be accomplished by using material A or B.

Task Materials

CE : Section 6 Products from Petroleum LQ P.5A B

(a) To make water pipes polyvinyl chloride iron(b) To make lenses perspex glass(c) To make shopping bags polyethene paper

In each case, state an advantage of(i) using A over B to accomplish the task.(ii) using B over A to accomplish the task.(You are not required to consider the price of the materials.)

(6 marks)

14. 99 6(b) (i) A teacher prepared an ethanol solution by fermentation of glucose using the following set-up.

(1) Suggest what X may be.(2) Explain why the lime water turned milky during the fermentation process.(3) Write the chemical equation for the fermentation of glucose.

(ii) The teacher used the ethanol solution obtained in (i) to carry out the following experiment on a redox reaction:

(1) State the observable change in the test tube.(2) Explain, in terms of oxidation number, whether potassium dichromate was oxidized or

reduced.(3) Give the structural formula of the product formed from ethanol in the reaction.

(iii) Suggest ONE reason for each of the following statements:(1) Drinking a small quantity of wine may be good for health.(2) Excessive drinking of alcoholic beverages may cause health problems.

(10 marks)

15. 00-6(c) Explain the following statements:(i) In cold weather, a person trying to warm up a room with a coal fire soon gets dizzy.(ii) Detergents can be used to clean up oil spillage in the sea.

(5 marks)

16. 00-7(b) Polystyrene can be prepared in the laboratory by heating a mixture of styrene and kerosene under reflux.(i) Draw a labelled diagram of the set-up used for heating the mixture under reflux.(ii) Suggest ONE safety precaution that should be taken when heating the mixture. Explain your

answer.(iii) Styrene has the following structure:

CE : Section 6 Products from Petroleum LQ P.6

C6H5CH=CH2

(1) What characteristic in the structure of styrene enables it to act as a monomer?(2) Write the chemical equation for the polymerization.

(iv)Disposable lunch boxes are commonly made of expanded polystyrene.(1) Suggest ONE reason why polystyrene should be expanded before it is used to make

disposable lunch boxes.(2) State whether you agree with the following statement. Explain your answer.

'Landfilling is better than incineration for the disposal of polystyrene wastes.' (8 marks)

17. 01-6(a) Soap powder usually contains washing soda, a hydrated form of sodium carbonate, which can

help reduce the hardness of water.(i) Explain why soap does not function well in hard water.(ii) With the help of an ionic equation, explain why washing soda can help reduce the hardness of water.

(4 marks)(c) (i) State the structural characteristics of a detergent. Hence, explain why detergents can

remove oily dirt.(ii) Suggest, with explanation, an environment consequence associated with the discharge of

waste water containing detergents into rivers and lakes.(5 marks)

18. 01-7(a)Polyethene is used in making shopping bas and its monomer is ethene.(i) Draw the electronic diagram of ethene, showing electrons in the outermost shells only.(ii) Name the type of polymerization involved in the production of polyethene.(iii)State one property of polyethene that makes it suitable for making shopping bags.(iv)(1) Suggest ONE way to dispose of polyethene wastes.

(2) Give ONE advantage and ONE disadvantage of the way you have suggested in (1).(6 marks)

19. 02-6(c)Ethyl ethanoate is an ester. It can be prepared by heating a mixture of ethanoic acid and ethanol under reflux in the presence of a catalyst.(i) What is the catalyst used in the preparation?(ii) Draw a labelled diagram of the set-up used for heating the mixture under reflux.(iii) Ethyl ethanoate is commonly used as a solvent. Explain why ethyl ethanoate can dissolve

iodine but cannot dissolve sodium iodide.(iv) Which ONE of the following hazard warning labels should be displayed on a bottle of ethyl

ethanoate?

(v) Draw the structure of another ester which has the same molecular formula as ethyl ethanoate, and give its systematic name.

(9 marks)

20. 02-8(c)Polyethyllene terephthalate (PET) is a polymer which is commonly used in making plastic bottles for fizzy drinks. PET has the following repeating unit:

(i) PET is formed by condensation polymerization. What is meant by the term 'condensation polymerization'?(ii) PET is a polyester formed from two monomers. Draw the structures of the monomers.

(3 marks)

CO

CO

OCH2CH2O

CE : Section 6 Products from Petroleum LQ P.7