Cq Petroleum Products

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Petroleum Products : 1985 2. (b) Poly-methyl 2-methyl acrylate (Perspex) is a polymer which has the following structure : H

CH3

H

C

C

C

H

H CO2CH3

CH3 C

H C

H CO2CH3

CH3 C CO2CH3

By heating some Perspex chips as shown in the diagram below, the liquid monomer of Perspex can be obtained : (i) (1) Draw the structure for the repeating unit in Perspex. (2) Hence, determine the percentage by mass of carbon in Perspex. (ii) What would be observed in testtube A when the Perspex chips are heated as shown? (iii) What is the function of the ice-water mixture? (iv) In which part of the laboratory should this experiment be carried out? Explain your answer. (v) Under suitable conditions, the monomer can be converted back to the polymer. (1) Write an equation for this reaction. (2) Name the type of polymerization reaction involved. (vi) In the plastics industry, used Perspex materials can be recycled. Suggest one reason for doing this. (vii) Give one use of Perspex and explain why it is used. (12 marks)

4. (b) The following chart shows some reactions of ethanol:

(i)* Draw a labelled diagram to show how reaction I can be performed on a test-tube scale in the laboratory. (ii) Describe briefly what would be observed when reaction II is carried out. (iii) (1) Give the reagents and conditions for carrying out reaction III in the laboratory. (2) Suggest a method for detecting the presence of the organic product in the reaction mixture. (iv) When a mixture of potassium dichromate and dilute sulphuric acid is spread on silica gel, it can be used to detect the presence of alcohol in the breath of a drunken driver. Describe what would be observed if alcohol were present. Explain briefly. (8 marks) Petroleum Products : 1986

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3. (b) Soap can be formed when sodium hydroxide reacts with an animal fat with the following structure : H

O

H C

O

C O

R

H C

O

C O

R

H C

O

C

R

where R = (CH2)16CH3

H

(i) Write a balanced equation for the formation of soap from this fat. (ii) With reference to its structure, explain why soap acts as an emulsifying agent. (iii)What would be observed if soap solution were mixed with sea water 2 (iv) Why does soap cause fewer pollution problems than some detergents? (7 marks) 3. (c) The repeating unit of nylon 66 is H N

(CH2 )6

H

O

N

C

O (CH2 )4

C

(i) Draw the structural formulae of the two monomers of nylon 66. (ii) Which kind of polymerization reaction produces nylon 66? (iii) Give one physical property of nylon and give one of its uses which is based on this property. (iv) Give ONE reason why it is difficult to dispose of nylon. (6 marks) 5. (b) For centuries, alcoholic drinks have been produced by the fermentation of carbohydrates. (i) What is the micro-organism commonly used in the fermentation process? (ii) Using glucose (C6H1206 ) as an example of a carbohydrate, write a balanced equation to represent this process. (iii) The ethanol content in alcoholic drinks produced by fermentation usually does not exceed 14%. Draw a diagram of a suitable laboratory set-up which could be used to concentrate the ethanol content in a sample to over 60%. (iv) State ONE physiological effect caused by the excessive intake of alcoholic drinks. (v) What would be observed if ethanol and acidified potassium dichromate solution were heated under reflux for a long time 2 Give the structural formula of the major organic product formed. (7 marks)

Petroleum Products : 1987

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2. (a) Liquid X is one of the following compounds CH3-CO2H CH2=CH-CH2-OH CH3-CH2-OH A B C The following experiments are carried out to study the reactions of X : Expt Procedure Observation I Add sodium to X. Effervescence occurs. II Add X to an acidified solution of potassium The orange solution turns dichromate, and shake the mixture. green. III Add X to a solution of bromine in The orange solution tetrachloromethane. becomes colourless, (i) Which of the three compounds A, B and C would give rise to the observation in (1) experiment I? (2) experiment II? (3) experiment III? Explain your answer in each case. (ii) Based on your answers in (i), state which compound is X. (iii) Name the type of reaction that occurs in experiment III. Write an appropriate equation. (iv) State ONE safety precaution necessary when carrying out experiment I in the laboratory. (10 marks) 4. (a) The flowchart below represents the hydrolysis of an ester, A, followed by the separation of the products :

O CH3

C O

CH2CH2CH3 heat with NaOH(aq)

under reflux (i) Write an equation for the hydrolysis of A. (ii) Give IUPAC names for X and Y. Aqueous solution containing compounds X and Y (iii) Draw a labelled diagram of the apparatus you would set up in the laboratory for distill refluxing A with aqueous sodium hydroxide. distillate containing Y residue containing X (iv) Why can Y be separated from X by distillation? (v) Explain why A is hydrolyzed in an alkaline medium rather than in an acidic medium. (vi) Briefly outline how soap is manufactured and write an appropriate equation. (11 marks)

5. (b) The structures of four carbon compounds are shown below : H

O H

C

H H

C H

H

O OH

NH2

C

H C

NH2

H

C Cl

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methanal methanol carbamide (urea) chloroethene (i) Which two of the above compounds would form a condensation polymer? Draw the simplest repeating unit for this polymer. (ii) Which one of the above compounds would undergo addition polymerization? Write an equation for the polymerization reaction. (iii) In the manufacture of electrical sockets, which of the polymers from (i) or (ii) should be used? Explain your choice. (iv) In the manufacture of plastic pipes, (1) which of the polymers from (i) or (ii) should be used? *(2) what type of moulding method is most suitable? (8 marks) Petroleum Products : 1988 4. (a) (i) Write an equation -to represent the polymerization of propene to form polypropene. (ii) When polypropene is strongly heated, the gaseous monomer can be obtained. (1) Draw a labelled diagram of the set-up you would use in the laboratory for heating polypropene and collecting the gaseous monomer, (2) State one potential hazard in this experiment, and suggest how it can be prevented. (iii) A new polymer can be obtained by polymerizing ethene and propene together. (1) Draw the structure of a repeating unit for this polymer. (2) Would you expect this polymer to be thermoplastic or thermosetting? Explain your answer. (3) In the plastics industry, products made from this new polymer can be recycled. Suggest one way of doing this. (10 marks) Petroleum Products : 1989 1. (b) The properties of four carbon compounds A to D are shown in the table below Carbon Melting Boiling Solubility in Products of complete compound point (oC) point (oC) water combustion A -205 -190 insoluble CO2 only B -182 -162 insoluble CO2 and H2O C 8 101 soluble does not burn D -98 65 soluble CO2 and H2O (i) Which of the four compounds could be (1) an alcohol? (2) a hydrocarbon? Explain your answer in each case. (ii) Which one of the remaining compounds could be a carboxylic acid? Suggest a chemical test for this compound and write an ionic equation for the reaction involved. (7 marks) 2. (b)

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A dilute solution of ethanol was produced by adding yeast to an aqueous solution of glucose (C6 H12 O6) and allowing the mixture to stand in the laboratory for a few days, as shown in the set-up below: (i) What would happen to the liquid level inside the long glass tube one day after the yeast had been added? Explain your answer. (ii) (1) Write an equation for the reaction occurring in the conical flask. (2) Name the process involved, and explain the function of yeast in this process. (iii) The above set-up could only produce a dilute solution of ethanol, even over a prolonged period. (1) Suggest a reason for this. (2) How can a more concentrated solution of ethanol be obtained from the mixture in the conical flask? (3) Describe briefly how you could test for the presence of' alkanol in the solution obtained in (2)? (iv) In some agricultural countries, ethanol mixed with petrol is often used as a fuel for motor vehicles. (1) Suggest an advantage of this practice. (2) Explain whether such a fuel would cause more pollution problems than using petrol alone. (12 marks) 4. (b) PVC, made by the polymerization of chloroethene, is often used in the manufacture of drainage pipes and plastic bags. (i) Write an equation for this polymerization. (ii) Calculate the number of repeating units in this polymer if it has a relative molecular mass of 40000. (Relative atomic masses : H = 1.00, C =12.0, C1= 35.5) (ii) (1) Name an appropriate moulding method for manufacturing PVC drainage pipes. (2) How could a length of straight PVC pipe be bent to fit the desired curvature in a particular drainage system? Explain your answer. (iv)Used PVC bags are usually destroyed by burning in incinerators. However, this would cause serious pollution problems. (1) Give TWO pollutants that could be produced during this process. (2) How could the release of these pollutants be minimized? Explain your answers. (12 marks)

Petroleum Products : 1990

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1. (a) The table below describes some reactions of liquid propan-l-ol : Experiment Result 1. Propan-l-ol is heated with acidified potassium with Substance X is formed, X sodium carbonate permanganate solution. produces effervescence 2. A mixture of propan-l-ol and substance X is heated A sweet smelling liquid Y is with concentrated sulphuric acid. formed. 3. Propan-l-ol is heated and the vapour passed over Gas Z is produced. heated broken porcelain (i) Name X. Write an ionic equation for the reaction of X with sodium carbonate solution. (ii) Write an equation for the formation of Y. Suggest TWO functions of the concentrated sulphuric acid in experiment 2. (iii) Draw a diagram to indicate how experiment 3 can be carried out in the laboratory, and how gas Z should be collected. (iv) Z can undergo addition polymerization to farm a polymer. (1) Name the polymer formed and draw the repeating unit, (2) State one household article that can be made from the polymer. Briefly describe how this article can be manufactured. (13 marks) 5. (b) A student heated a mixture of aqueous sodium hydroxide and ethyl ethanoate for some time using the following set-up : (i) (1) Name the type of reaction that took place. Write an appropriate equation for the reaction. (2) What would be observed when the reaction was complete? (3) Give an industrial application of this type of reaction. (ii) What is the function of t 'cold finger"? (iii)State a potential hazard in the set-up shown above. (iv) The quantity of the products obtained in this experiment was much less than that expected. (1) Give an explanation for this. (2) Draw a labelled diagram of a completely different set-up to illustrate how the quantity of the products can be increased by using the same quantities of reactants. (9 marks)

Petroleum Products : 1991

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1. (b) A vegetable oil, X, can undergo reversible hydrolysis in the presence of sulphuric acid as given by the following equation : X + 3H2O

CH2 + 3RCOOH (where R represents OH OH OH alkyl groups) propane-1,2,3-triol CH2

CH

(i) Write the structural formula of X. (ii) What is the function of sulphuric acid in this reaction? X can be hydrolyzed more effectively by using sodium hydroxide solution instead of sulphuric acid, and the products are propane-1,2,3-triol and Y. (iii) Name this process. (iv) Write the structural formula of Y. (v) Using the concept of chemical equilibrium, explain why the use of sodium hydroxide solution is more effective. When a solution of Y is slowly added, with stirring, to a mixture of peanut oil and water, a milky solution is obtained. (vi) Based on the structural formula of Y, explain why a milky solution is formed. (vii) Name the process leading to tee formation of the milky solution and suggest one domestic application of this process. (12 marks) 2. (b) The following diagrams show three plastic items. The universal adapter is made of thermosetting plastic while the other two are made of thermoplastics.

Universal adapter

Foam lunch box

Food wrap

(i) Explain why thermoplastics are not suitable for making universal adapters. (ii) The foam lunch box is made from a plastic containing a trapped gas. Name the plastic that is commonly used and state the purpose of trapping a gas within the plastic. (iii) (1) Name a plastic that is commonly used to make food wrap, and write an equation to show the formation of the plastic from its monomer. (2) State the moulding method used to make food wrap. (6 marks) Petroleum Products : 1992 3. (a) Fermentation of cooked rice produces an alcoholic drink which contains about 8% of ethanol.

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(i) Describe briefly how such fermentation can be carried out in the laboratory, (ii) How can the alcoholic drink be concentrated so as to raise its ethanol content to about 30%? (iii) Some alcoholic drinks become sour when exposed to air for some time. Suggest a reason for this. (iv) State one health hazard and one social problem associated with the excessive taking of alcoholic drinks. (8 marks) 4. (a) (i) The structure of polymer X can be represented by following diagram : H

H

H

C

C

C

C

H

H

H

H

H

H

C

C

C

C

H

H

H

where represents a group containing carbon and hydrogen atoms only.

(1) Draw the structure of the monomer of X. (2) Name an example of a polymer with the structure of X. (3) Two separate pieces of X are strongly heated as shown in diagrams A and B below: What would be observed in each case? Explain your answer. (ii) Upon analysis, 5.00 g of the monomer of X are found to contain 4.62 g carbon. If the relative molecular mass of the monomer is 104, deduce its molecular formula. (Relative atomic masses : H=1.0, C=12.0) (9 marks) Petroleum Products : 1993 1. (c) Alkenes can be obtained from petroleum fractions by a process called 'cracking'. Using a suitable petroleum fraction, a student carried out this process in the laboratory and collected the gaseous product over water. (i) What is 'cracking'? (ii) Draw a laballed diagram of a laboratory set-up that can be used for carrying out the process and collecting the gaseous product. (iii)An important safety precaution in the experiment is to prevent sucking back. (1) What is the potential hazard if sucking back occurs? (2) How can sucking back be prevented? (iv) If the gaseous product decolorizes a solution of bromine in tetrachloromethane, can you conclude that the gaseous product is ethene? Explain your answer. (8 marks)

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

where

-

Na+

represents a hydrocarbon tail and represents an anionic part attached to the hydrocarbon tail.

(1) Using the above representation, 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 : + ClCan anionic and cationic detergents be used together? Explain your answer. (6 marks)

Petroleum Products : 1994 3. The following diagrams show some items made of synthetic polymers.

(a) (b) (c) (d)

Electric switch Plastic bag Shirt Which of the above items is most likely to be made of thermosetting plastics? Explain your answer. Name one synthetic polymer which is suitable for making the plastic bag. Suggest a suitable moulding method used in making the electric switch. Terylene, the polyester fibre used for making the shirt is synthesized from ethane-1,2diol, 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)

5. (a) A domestic drain cleaner named 'RAINBOW' contains concentrated sulphuric acid as the active ingredient. A student carried out the following experiment to determine the concentration of sulphuric acid in 'RAINBOW'. 1.0 cm3 of 'RAINBOW' was diluted to 500 cm3 with distilled water. 25.0 cm3 of the diluted solution were measured and transferred to a conical flask. The solution in the flask required 18.2 cm3 of 0.10 M sodium hydroxide solution for complete neutralization.

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(i) Name the apparatus used to measure 25.0 cm3 of the diluted solution. (ii) Calculate the molarity of sulphuric acid in 'RAINB0W'. (iii) Suggest ONE disadvantage of using 'RAINBOW' for cleaning drains. (iv) State ONE safety precaution needed when using 'RAINBOW'. Explain your answer. (v) If 'RAINBOW' is poured into drains blocked with fat, the fat can be removed. Assuming the formula of fat is H H

C

OCOR

H

C

OCOR

H

C

OCOR

(R represents an alkyl group),

H

explain how 'RAINBOW' can remove the fat. (8 marks)

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)

Petroleum Products : 1995 7. (b) The following flow diagram shows the conversion of a compound X to an acid Y. X

Ethanol

oxidation

Y

X can rapidly decolorize a solution of bromine in 1,1,1-trichloroethane.

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(i) What is X? Name the industrial process by which X is converted to ethanol. (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) 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+lCOONa 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 :

CH3

CH3 CH3 CH3 CH3 H H H C C C C + C C C SO3 Na H H H H CH3 CH3 CH3

(1) that 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)

Petroleum Products : 1996 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 .

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(2) What are the TWO main processes involved in the production of monomer d 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) Petroleum Products : 1997 7. (b) The structure of five compounds, I, II, III, IV and V are shown below:

In the above structures, carbon atoms and carbon atoms.

represents a saturated hydrocarbon chain containing 1 to 6 represents a saturated hydrocarbon chain containing 12 to 20

(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 stnicture of the soapy detergent produced. (3) Briefly explain the emulsifying action of the detergent when it is used to remove greasy dirt. (10 marks) Petroleum Products : 1998 2. 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) 7. (b)

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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. (You may assume that no other chlorine-containing compounds are present in the waste.) (RAM’s : H=1.0, C=12.0, Cl=35.5; molar volume of gas at room temperature and pressure = 24.0 dm3) (9 marks)

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

w a te r o u t X

(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 the reaction mixture.

w a te r in

a m ix tu re o f p ro p a n -1 -o l a n d a c id ifie d p o ta s s iu m d ic h ro m a te s o lu tio n

p u m ic e s to n e s

H EAT

The student used the propanoic acid obtained to carry out the following experiment : a m ix tu re o f p ro p a n o ic a c id , m e th a n o l a n d a few d ro p s o f c o n c e n tra te d s u lp h u ric a c id h o t w a te r

a fte r 1 0 m in u te s

s o d iu m c a rb o n a te s o lu tio n

(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.

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(8 marks)

Petroleum Products : 1999 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.

a q u e o u s s o lu tio n o f g lu c o s e w ith s u b s ta n c e X a d d e d

lim e w a te r

(ii) The teacher used the ethanol solution obtained in (i) to carry out the following experiment on a redox reaction: e th a n o l vapour

a ir

(1) State the observable change in the test tube. (2) Explain, in terms of oxidation number, whether potassium dichromate was oxidized or e th a n o l te s t tu b e reduced. s o lu tio n (3) Give the structural formula of the a c id ifie d p o ta s s iu m product formed from ethanol in d ic h ro m a te s o lu tio n 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) to p u m p

1. Each of the tasks listed in the table below can be accomplished by using material A or B. Task (a) To make water pipes (b) To make lenses (c) To make shopping bags

Materials A Polyvinyl chloride Perspex Polyethene

B iron Glass 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)

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Petroleum Products : 2000 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: 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) 8. (b) In some countries, ‘gasohol’ (a mixture of petrol and ethanol) is used as fuel for cars. (i) Explain why burning gasohol causes less air pollution than burning petrol. (ii) Ethanol can be manufactured from a petroleum product. Name for manufacturing process and write the chemical equation for the reaction involved. (iii) Ethanol can also be manufactured by another process. Name this process. (iv) Of the two processes you have mentioned in (ii) and (iii), which one is better for the manufacture of ethanol in gasohol? Explain your answer. (5 marks)