was heated strongly in the absence of air. + 2C + C

Transcription

1 Q. (a) The hydrocarbon C 6 34 was heated strongly in the absence of air. This is one of the reactions which took place: C 6 34 C C 6 + C 4 This type of reaction is carried out because there is a greater demand for the products than for the original hydrocarbon. Suggest two reasons for this () (b) A molecule of the compound methane, C 4, can be shown like this: Draw a molecule of the compound ethene, C 4. () (c) Small molecules of substances called monomers can be joined together in polymerisation, eg. ethene poly (ethene). (i) Complete the equation below to show formation of the polymer from the monomer propene. () Page of 68

2 Suggest the name of the polymer formed. () (Total 6 marks) Q. The equation below shows the cracking of a hydrocarbon compound into two different compounds, A and B. (a) State two differences between the structures of compounds A and B. () (b) Why is compound A useful in industry? () (Total 3 marks) Q3. Poly(ethene) is a long-chain saturated hydrocarbon. The formula for part of the polymer chain is: (a) Write the structural formula of the small molecule from which poly(ethene) is made. () Page of 68

3 (b) Saturated hydrocarbons, such as propane, are fuels. Write a balanced equation for the complete combustion of propane, C (3) (Total 5 marks) Q4. The table shows some of the products which are obtained from the fractional distillation of crude oil. Fraction A B C Nature of products a mixture of gases a mixture of low boiling point liquids a mixture of high boiling point, yellow liquids (a) For each of the fractions A C give the name of an organic substance which could be part of the fraction and state a use for it. A... Use... () B... Use... () C... Use... () (b) When burned in excess air, all the substances in fractions A C form the same two compounds. Give the formulae of these two compounds.... and... () (Total 7 marks) Page 3 of 68

4 Q5. Crude oil is a mixture of long-chain hydrocarbons. It is cracked to produce a mixture of smaller alkanes and alkenes. Among the gases formed are ethane and ethene. (a) Write the structural formula for: (i) ethane () ethene () (iii) Give an example of one chemical reaction which both ethane and ethene undergo. () (iv) Describe how to distinguish between ethane and ethene. Include a description of the practical method you would use and what you would expect to observe. (3) (b) Ethene may be polymerised to form a polymer. Give the name of the polymer and a use for it. Name... Use... () (Total 7 marks) Page 4 of 68

5 Q6. The diagram shows a reaction which takes place in an oil refinery. (a) X, Y and Z are all examples of which type of compound? () (b) What type of chemical reaction takes place when compound X is converted into compounds Y and Z? () (c) Compounds Y and Z are both useful substances. Compound Y is unsaturated. Compound Z is saturated. (i) Suggest one use for compound Y. () Suggest one use for compound Z. () (Total 4 marks) Q7. (a) Some hydrocarbons are used as fuels in power stations. The table gives the boiling points of four hydrocarbons. ydrocarbon Boiling point in C W 65 X 60 Y 40 Z 80 (i) Which of these hydrocarbons are gases at room temperature (0 C)? () Page 5 of 68

6 Which of these hydrocarbons has the largest molecules? () (iii) Which of these hydrocarbons ignites most easily? () (b) Some hydrocarbons are used to produce polymers. Which type of hydrocarbons can be converted into polymers? () (Total 4 marks) Q8. The diagrams show the percentages of the four main fractions produced from two samples of crude oil, A and B. Page 6 of 68

7 (a) The light fraction contains hydrocarbons used for the manufacture of useful chemicals such as polymers. Which one of the samples, A or B, would be more useful for the manufacture of polymers? Explain your answer. () (b) eptane (C 7 6 ), is one of the hydrocarbons used for the manufacture of poly(ethene). The first stage of the process is the production of ethene and another hydrocarbon from heptane. C heptane ethene (i) In the box, draw the structural formula of the other hydrocarbon produced. () Page 7 of 68

8 Describe how the reaction is carried out. () (Total 5 marks) 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. exane and butane are alkanes. Describe the structure of alkanes (3) Page 8 of 68

9 (b) Ethene is used to make poly(ethene). This process is called polymerisation. Explain what is meant by polymerisation () (Total 5 marks) Q0. The label has been taken from a tube of umbrol Polystyrene Cement, a glue used in model making. (a) The solvent used is,,-trichloroethane. The structural formula of this molecule is: (i) What do the lines between the atoms represent? () Page 9 of 68

10 State whether,,-trichloroethane is saturated or unsaturated. Give one reason for your answer. () (iii),,-trichloroethane is being replaced in favour of a better solvent. Use information on the label to help you to suggest why. () (b) Polystyrene is a plastic. Plastics are polymers which are made by the process of polymerisation. (i) What is meant by polymerisation? () The table gives information about monomers and the polymers made from them. Complete the table. (3) (Total 8 marks) Page 0 of 68

11 Q. Crude oil is a mixture of many compounds. The diagram below shows some of the processes that take place in a petrochemical plant. (a) Name the process which takes place in the COLUMN. () (b) Name the type of reactions which take place in: (i) REACTOR... REACTOR... () (c) The petroleum gases contain ethane, C6 and propane, C38. The structure of a molecule of ethane can be represented as: ethane Draw the structure of a molecule of propane in the space below. propane () (d) Ethane and propane are said to be saturated hydrocarbons. What does saturated mean when used to describe hydrocarbons? () Page of 68

12 (e) Many molecules of ethene join together to form poly(ethene) in REACTOR. Complete the diagram below to show the formation of poly(ethene). () (Total 7 marks) Q. Propane and ethene are both important hydrocarbons. (a) (c) Complete the table by adding the formula of the ethene molecule and the structure of the propane molecule. 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? () Page of 68

13 What type of polymerisation reaction is shown in the equation? () (Total 4 marks) Q3. Crude oil is a mixture of a large number of compounds most of which are hydrocarbons such as the molecule shown below. (a) What is a hydrocarbon? () (b) What is the chemical formula of the molecule shown above? () (e) The cracking of large molecules obtained from crude oil is one of the important processes in an oil refinery. Cracking involves the thermal decomposition of large molecules. The diagram below shows an apparatus that can be used to demonstrate cracking in the laboratory. The porous pot acts as a catalyst in the reaction. (i) What happens during thermal decomposition? () Page 3 of 68

14 What effect does the porous pot catalyst have on the reaction? () (iii) Complete the equation below for the cracking of the molecule. C 0 4. C 0 4 C () (Total 6 marks) Q4. 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 (C 4 0 ), a hydrocarbon in crude oil, can be cracked to produce two different hydrocarbons, ethane (C.4) and ethene (C 4 ) (i) For cracking to happen what needs to be done to the hydrocarbon? () Complete the equation for the cracking of butane using displayed formulae. () (iii) Complete the balanced chemical equation far the complete combustion of ethane in oxygen....c.4(g) +...(g)...(g) +...(l) (3) Page 4 of 68

15 (b) The second stage is the formation of the plastic material by polymerisation. Describe how ethene (C 4 ) forms poly(ethene). You do not need to give the reaction conditions or the names of catalysts. (3) (Total 0 marks) Q5. The high demand for petrol (octane) can be met by breaking down longer hydrocarbons, such as decane, by a process known as cracking. (a) Apart from heat, what is used to make the rate of this reaction faster?... () (b) Octane is a hydrocarbon. (i) What does hydrocarbon mean? () Give the molecular formula of octane. () (c) The hydrocarbon X is used to make poly(ethene). (i) What is the name of X? () Page 5 of 68

16 What is the name of the process in which X is changed into poly(ethene)? () (Total 5 marks) Q6. The molecular formulae of two hydrocarbons M and N are given. M = C 4 0 N = C 4 8 (a) M reacts with chlorine to form C 4 9 Cl. (i) Write a balanced chemical equation for the reaction of chlorine with M. () Name this type of reaction. () (b) A displayed structural formula for N is: Draw a displayed structural formula of a compound which is an isomer of N. () Page 6 of 68

17 (c) Complete the boxes to show the displayed structural formula for each of the products formed. () (Total 6 marks) Q7. (a) Alkenes can be made by cracking large alkane molecules. (i) Explain how the cracking process is carried out. () Give a chemical test which would show the difference between an alkene and an alkane. Test... Result of test... () Page 7 of 68

18 (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. () Name the polymer formed from ethene. () (iii) Explain one important problem caused by the everyday use of this polymer. () (Total 8 marks) Q8. In 939 Roy Plunkett opened the valve on a new cylinder of tetrafluoroethene gas. No gas came out! e 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. () Page 8 of 68

19 (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. () (c) Describe how this addition polymer forms from monomers. (3) (Total 6 marks) Page 9 of 68

20 Q9. The diagram shows an apparatus that can be used to carry out cracking reactions in a laboratory. (a) Why is aluminium oxide or broken porcelain used? () (b) Paraffin contains decane. The cracking of decane can be represented by the equation below. A decane molecule is split into two smaller molecules. Complete the equation by adding the formula of the other product. C 0 (l)... (l) + C 4 (g) decane () (c) Would you expect C 4 molecules to collect at position A or B shown on the diagram? Position... Explain your answer. () Page 0 of 68

21 (d) Cracking reactions involve thermal decomposition. What is meant by thermal decomposition? () (e) Explain, as fully as you can, why cracking is used in the oil industry. To gain full marks in this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words. (3) (f) The cracking reaction produces a mixture of products. The mixture contains hydrocarbons with different boiling points. Suggest a method of separating this mixture. () (Total 9 marks) Page of 68

22 ## 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! (a) State why plastic window frames need no painting or maintenance. () (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? () Complete the diagram to represent how poly(chloroethene) is formed from chloroethene. (3) (iii) Explain what is meant by the term polymerisation. () Page of 68

23 (iv) Why is this an addition polymerisation? () (Total 8 marks) Q. Known crude oil reserves are being used up rapidly. Crude oil is used to produce many useful fuels, such as petrol. One way to conserve crude oil reserves would be to increase the production of bio-fuels. (a) Ethanol can be produced for use as a bio-fuel. Cars can be powered by ethanol or ethanol petrol mixtures. Sugar cane can be fermented to give a mixture of water (boiling point 00 C) and ethanol (boiling point 78 C). (i) ow can ethanol be separated from water? () Ethanol, C 5 O, burns to release heat energy. Complete the balanced symbol equation by writing in the formulae of the two products. C 5 O + 3O () (b) The cost of producing a bio-fuel, such as ethanol, by fermentation, is at least three times higher than the production cost of petrol. It costs less to produce ethanol from alkanes. In the production, the vapour of an alkane is passed over a hot catalyst. Ethene is then converted into ethanol. (i) What has happened to the hexane to produce ethene? () Page 3 of 68

24 Complete the structural formula for ethene, C 4. C C () (iii) Name the compound that is added to ethene to produce ethanol, C 5 O. () (c) As explained in parts (a) and (b), ethanol can be made using either sugar or alkanes as the starting material. Evaluate the advantages and disadvantages of using these two starting materials to produce ethanol (4) (Total 0 marks) Page 4 of 68

25 Q. Polymers are used to make many materials that people need. (a) Plastic bags are used to carry, protect and store food. Plastic bags are made from polymers. (i) Ethene is the small molecule (the monomer) used to make the polymer for this plastic bag. Name the polymer that is made from ethene. () Use the correct word from the box to complete the sentence about ethene. condensing corroding cracking Ethene is made by breaking down large hydrocarbon molecules into smaller hydrocarbon molecules by a process called... () (iii) The hydrocarbon ethene has the formula C 4 Complete the sentence about ethene. Ethene is a hydrocarbon made up of carbon and... atoms. () (b) The hydrocarbons used to make ethene come from crude oil. The properties of hydrocarbons are linked to the number of carbon atoms in their molecules. Number of carbon atoms Boiling point in C Page 5 of 68

26 (i) Use the data in the table to complete the bar chart. () What happens to the boiling point of a hydrocarbon as the number of carbon atoms increases? () (iii) All the hydrocarbons in the table are found in petrol. Petrol is one of the fractions separated from crude oil. Describe how the fractions are separated from crude oil. () Page 6 of 68

27 (c) Most plastic bags that are made of hydrocarbons are not biodegradable. Used plastic bags can be: dumped into large holes, which is called landfill burned to give out heat energy, which would produce large amounts of gases. Would burning used plastic bags be better for the environment than dumping them in landfill? Explain your answer. () (Total 0 marks) Q3. Scientists study the atmosphere on planets and moons in the Solar System to understand how the Earth s atmosphere has changed. (a) Millions of years ago the Earth s atmosphere was probably just like that of Mars today. The table shows data about the atmospheres of Mars and Earth as they are now. Mars Earth nitrogen 3% nitrogen 78% oxygen trace oxygen % water trace water trace carbon dioxide 95% carbon dioxide trace Average surface temperature 3 C Average surface temperature 5 C Suggest what has caused the main gases in the Earth s atmosphere of millions of years ago to change to the present-day atmosphere () Page 7 of 68

28 (b) Titan is the largest moon of the planet Saturn. It has an atmosphere that, like the Earth s, contains mainly nitrogen. Methane is the other main gas. Main gases in Titan s atmosphere Percentage (%) Boiling point in C Nitrogen Methane 5 64 Average surface temperature 78 C When it rains on Titan, it rains methane! Explain why () (c) Ultraviolet radiation from the Sun produces simple alkenes, such as ethene and propene, from methane in Titan s atmosphere. (i) Draw the structure of propene, C 3 6, to show the covalent bonds. () Explain how propene molecules form a polymer. You should name the polymer formed. (3) (Total 8 marks) Page 8 of 68

29 Q4. Tablet containers are often made from two different polymers. (a) Ethene, C 4, and propene, C 3 6, can be made from crude oil. (i) Complete the following sentence. Ethene and propene are called hydrocarbons because they are made up of carbon and... atoms only. () Ethene molecules are used to form poly(ethene) molecules. Complete the diagram to show the poly(ethene) molecule. Ethene molecules Poly(ethene) molecule () (b) The tablet containers could be disposed of in a landfill site or could be recycled. (i) Suggest two reasons why disposing of the tablet containers in a landfill site could cause problems () Page 9 of 68

30 Suggest one reason why recycling the tablet containers would be difficult () (Total 6 marks) Q5. Crude oil is the source of many useful materials. Crude oil is separated into fractions by fractional distillation. (a) Describe how the naphtha fraction separates from the other fractions. () (b) The naphtha fraction is often used to make other useful materials. This involves the cracking of hydrocarbons in the naphtha fraction. For example: decane hexane + ethene C 0 C C 4 Page 30 of 68

31 (i) (iii) Balance the symbol equation given above. Describe how cracking is carried out. Why does ethene have different chemical properties from decane and hexane? () () () (c) Ethene is used as the starting material for many polymers. The most common polymer is poly(ethene). One hydrocarbon molecule in poly(ethene) will contain thousands of carbon atoms. Complete the diagram to show the bonds in ethene. C C () Page 3 of 68

32 (d) Read the following information. Landfill, Incineration, Recycling and Re-use of Poly(ethene) People could be encouraged to re-use their poly(ethene) bags and containers. Recycling poly(ethene) saves raw materials and energy needed to make new plastic. When polymers are recycled the plastics must be collected, transported, sorted into different types by hand and washed. This requires the use of fossil fuels and is expensive. Poly(ethene) can be burnt in an incinerator with other household waste. The heat released could be used to make steam to drive an electric generator. Surplus heat could be used to heat greenhouses used for growing vegetables. Incineration at too low a temperature can produce harmful substances. The residue (ash) has to go to landfill. Landfill is probably the easiest way to dispose of polymers and it is cheap. Polymers are often mixed in with other household rubbish. ousehold waste does not get sorted into different materials because it is disposed of in the same hole in the ground. When the hole is eventually full, the waste is covered by a layer of soil to stop it smelling. The waste gets compressed under its own weight. Most polymers, such as poly(ethene), are not biodegradable so will remain in the ground forever. You are asked to decide which option for the disposal of poly(ethene) will be put forward in your area. You decide that recycling is the best option. Suggest one economic argument and one environmental argument that will be made against recycling. Page 3 of 68

33 For each argument made, how will you persuade those making the argument to accept your option? (You must use only one sentence for each argument made against your decision and only one sentence for your response to it.) (4) (Total marks) Q6. Plastics are used to make many everyday items, such as the body of the kettle. (a) Complete the sentences by drawing a ring around the correct words. (i) The plastic is made from many small molecules called catalysts monomers polymers () Propene is produced by cracking some of the fractions that are crude oil separated from limestone metal ores () Page 33 of 68

34 (b) After a few years the kettle no longer worked. Some parts of the kettle are made of plastic. Some parts of the kettle are made of stainless steel. The owner of the kettle disposed of it in a landfill site. Consider these statements. Suggest three reasons why the kettle should not be disposed of in a landfill site (3) (Total 5 marks) Q7. (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). () PEX is a shape memory polymer. What property does a shape memory polymer have? () Page 34 of 68

35 (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. (3) Page 35 of 68

36 (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. The low-grade ore is powdered and concentrated. Smelting is carried out in an oxygen flash furnace. This furnace is heated to 00 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. Fractional distillation 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. (4) (Total 0 marks) Q8. Crude oil is used to make useful substances such as alkenes and plastics. (a) The alkene shown is ethene. Page 36 of 68

37 (i) Tick ( ) the correct formula for ethene. Formula ( ) C 4 C 4 C 6 () Tick ( ) the name of the plastic formed when many ethene molecules join together. Name of plastic ( ) Poly(ethene) Poly(ethanol) Poly(propene) () (b) Read the article about plastics and then answer the questions. TE PROBLEM WIT PLASTIC WASTE The UK produces about 3 million tonnes of plastics from crude oil every year. Most of the litter found on UK beaches is plastic waste. 80% of the plastics produced end up in landfill sites. The UK recycles only 7% of plastic waste. (i) Draw a ring around the correct answer in the box to complete the sentence. Litter that is plastic waste needs to be removed from beaches because it decomposes is flammable is not biodegradable. () Suggest a problem caused by 80% of the plastics going to landfill sites. () Page 37 of 68

38 (iii) The UK government has set a target to recycle 30% of plastic waste. ow are resources saved by recycling more plastics? () (Total 5 marks) Q9. Water sold in plastic bottles has a high carbon cost. The carbon cost depends on the amount of carbon dioxide emitted in making and transporting the product. The more carbon dioxide emitted, the higher the carbon cost. (a) Plastic water bottles are made from a polymer. The polymer is made from ethene. Ethene is made by cracking hydrocarbons. (i) Name the polymer made from ethene. () Ethene can be made by cracking the hydrocarbon pentane, C 5. C 5 C 4 + C 3 8 Explain why there is a carbon cost for the process of cracking a hydrocarbon. () Page 38 of 68

39 (b) The diagram shows information about water sold in plastic bottles in the UK. The diagram also shows the average distances that water and plastic bottles are transported. Suggest how the high carbon cost of water sold in plastic bottles could be reduced. (3) (Total 6 marks) Q30. Water sold in plastic bottles has a high carbon cost. The carbon cost depends on the amount of carbon dioxide emitted in making and transporting the product. The more carbon dioxide emitted, the higher the carbon cost. (a) Plastic water bottles are made from a polymer. The polymer is made from ethene. Ethene is made by cracking hydrocarbons. (i) Name the polymer made from ethene. () Page 39 of 68

40 Ethene can be made by cracking the hydrocarbon pentane, C 5. C 5 C 4 + C 3 8 Explain why there is a carbon cost for the process of cracking a hydrocarbon. () (b) The diagram shows information about water sold in plastic bottles in the UK. The diagram also shows the average distances that water and plastic bottles are transported. Suggest how the high carbon cost of water sold in plastic bottles could be reduced. (3) (Total 6 marks) Page 40 of 68

41 M. (a) smaller, more useful molecules more reactive (molecules)/(molecules) used to make plastics more easily ignited/better fuels produces unsaturated compounds/alkenes any two for mark each (b) gains mark but gains marks (c) (i) for mark poly(propene) (N.B. brackets not required; allow polypropylene ) for mark [6] ## (a) Compound A has fewer C atoms or Compound B has fewer atoms Compound A has C = C/double bond or Compound A is unsaturated each for mark (accept converse i.e compound B has not...) Page 4 of 68

42 (b) Compound A is reactive or can be used to make many substances or can be used in polymerisation/making plastics/named plastic or can be used as a fuel any one for mark [3] M3. (a) C=C do not accept C 4 four s only, two attached to each carbon credit C C for two marks (b) C O 3CO + 4 O two correct formulae LS can be in either order two correct formulae RS can be in either order correctly balanced, consequential marking allowed for 0 O [5] M4. (a) Substance Use A any pair from award one mark for a correct use for an incorrect fuel methane or fuel natural gas or refinery gas ethane propane fuel or making ethene for polymerisation bottled or camping gas or fuel accept relevant trade names e.g. Calor Gas Page 4 of 68

43 butane bottled or camping gas or fuel or lighter fuel B any pair from petrol or gasoline accept car engines do not credit just cars fuel for cars naptha paraffin or kerosene accept jet or aircraft fuel petrol or chemicals or feedstock or solvent heating fuel or aviation fuel C any pair from naptha petrol or chemicals or feedstock or solvent paraffin or kerosene diesel or diesel oil or (light) gas oil heating fuel or aviation fuel vehicle fuel or heating fuel (lubricating) oil lubricating or oiling qualified, eg. oiling a gate fuel oil industrial or heating fuel heavy gas oil fuel for stationary or slow speed diesel engines (b) CO and O both required [7] Page 43 of 68

44 M5. (a) (i) do not credit C 3 C 3 do not credit C 4 (iii) burn or react with oxygen or combustion or oxidation accept react with chlorine (iv) bubble each gas through (test tube containing) bromine water accept add bromine (water to gas collected) or burn ethene decolourises it or turns the brown colourless accept ethene burns with smoky flame do not accept makes it go clear ethane does not affect it or leaves it brown accept ethane burns with clear flame note carefully the spelling of ethene and ethane (b) both the correct name and use are required for the mark poly (ethene) or polythene; any soft or pliable plastic article or any suitable harder plastic item accept polyethene or polyethylene [7] M6. (a) hydrocarbon (b) thermal decomposition / cracking Page 44 of 68

45 (c) (i) making polymers / poly(e)thene accept plastic (bags) fuel [4] M7. (a) (i) X and Y both needed (iii) Z X (b) unsaturated / alkenes / those with double (C = C) bonds [4] M8. (a) B because it contains more of the light fraction) Quantitative answer e.g. B has 30%, A has 0% / 0% more /.5 times more (b) (i) heat catalyst if neither mark gained allow cracking for mark [5] Page 45 of 68

46 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) C n n+ (b) many small molecules/ monomers accept many unsaturated molecules or alkenes join together to form a large / long molecule / polymer [5] M0. (a) (i) bonds / pair of electrons / shared electrons for one mark saturated since it has single bonds / no double bonds / no multiple bonds / maximum number of atoms attached for one mark (iii) sensible answer (e.g. it is harmful) or better solvent could be used on expanded polystyrene or foam for one mark (b) (i) simply writing monomers form / react to form polymers gains no mark monomers join / bond / combine / link to form polymers = 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 ( marks) many monomers join to form a polymer ( marks) monomers join to form a large molecule / long chain ( marks) many molecules join together ( marks) for mark each Page 46 of 68

47 polyethene / poly(ethene) / polythene don t worry too much about the exact positioning of the C65 at the end of the bond placement of linking bonds inside / outside brackets is not important must have n for mark each [8] M. (a) (fractional) distillation/fractionation for mark (b) (i) cracking/decomposition for mark polymerisation/addition reaction for mark (c) (Must have atoms) for mark (d) contains only/all single bonds no double bonds contains maximum number of atoms carbon atoms bonded to 4 other atoms (not 4 atoms) will not undergo addition reactions any for mark Page 47 of 68

48 (e) = marks (n must be on (right)) = marks (n on left = mark) = mark = mark (Double bond loses both marks) = 0 marks OR = marks (for both a minimum of 4 carbon atoms) = mark = marks Page 48 of 68

49 M. (a) C 4 (b) C 5 = mark = mark [7] C C C Accept even if in wrong columns (c) (i) polythene or poly(ethene) addition [4] M3. (a) A compound made from carbon and hydrogen (not mixture etc.) (e) (i) Break down by heat (iii) Speeds up reaction C 8 6 each for mark 4 [6] Page 49 of 68

50 M4. (a) (i) heat accept increase temperature ignore pressure with a catalyst accept displayed formulae only (iii) O CO + O ignore state symbols correct balancing accept only if reactants and products correct Page 50 of 68

51 (b) double bond breaks many (ethene) molecules accept many monomers bond together accept join or combine for bond accept for first marks ignore unsaturated becomes saturated [0] M5. (a) catalyst (b) (i) made up of only carbon and hydrogen C 8 8 (c) (i) ethene polymerisation [5] M6. (a) (i) C Cl C 4 9 Cl + Cl reactants products ignore incorrect balancing no state symbols required substitution / chlorination Page 5 of 68

52 (b) atoms not necessary (c) [6] M7. (a) (i) by heating pressure is neutral using a catalyst/pot/ceramic/porcelain/aluminium oxide use bromine water/(alkaline) permanganate accept bromine 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 (b) (i) either of these must show bonds at end or not on ends allow 3 instead of n not any other number Page 5 of 68

53 poly(ethene) brackets not essential accept polythene (iii) large amount of waste polymer/poly(ethene)/polythene/litter accept large amount of crude oil or finite resource used 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 [8] M8. (a) poly(tetrafluoroethene) or polytetrafluoroethene accept PTFE or Teflon (b) double bond all other atoms and bonds correct including F for fluorine ignore n in front or = mark = mark CF = CF = mark do not accept structures with more than C atoms Page 53 of 68

54 (c) any three from: many monomers / (small) molecules / tetrafluoroethene molecules allow many tetrafluoroethenes many particles alone is insufficient do not accept many polymers (monomers, molecules etc.) join / bond / link / combine / attach allow many particles join allow many atoms join do not accept collide / add ignore polymerise do not accept many polymers join to form one molecule or to form a long-chain or to form a large molecule no other substances are produced / one substance formed (definition of addition) idea of double bond breaking / opening / opens / bond being used to join to another molecule or the double bond becomes a single bond 3 [6] M9. (a) catalyst or speeds up the reaction (owtte) accept lowers activation energy not just helps reaction to take place ignore increased surface area (b) C 8 8 allow 8 C 8 must be upper case do not accept powers (c) B because it is a gas or because it has small molecules or because they are small position and reason for mark allow it has a lower / very low boiling point than A ignore references to solubility accept does not condense do not accept light molecules or bubbles into B do not accept it is small (d) breakdown of a substance (owtte) do not accept decompose unqualified by the action of heat (owtte) Page 54 of 68

55 (e) Quality of written communication if the written communication makes sense and it is in context then award Q mark Q Q large to small molecules or scientific word that implies smaller, e.g. alkene / ethane / petrol any name or formula of alkane / alkene smaller than decane either advantages of smaller molecules or disadvantages of larger molecules e.g. hydrocarbons with large molecules are limited in their usefulness or converse for smaller molecules large hydrocarbon molecules do not ignite easily / do not flow easily / are not very volatile or converse for smaller molecules more large hydrocarbon molecules are produced than are needed or converse for smaller molecules smaller molecules are useful as fuels alkenes / products can be used to make polymers (f) (fractional) distillation accept fractionation accept good description do not accept just diagram [9] M0. (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 (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 Page 55 of 68

56 single bond between carbon atoms all atoms correct + linking bonds (linking bonds need not go through bracket) n moved to bottom right of bracket i.e. is below way on the right first marks are possible for chain structures accept [ CCl C ] n (iii) many molecules or many monomers 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 nd mark (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 [8] Page 56 of 68

57 M. (a) (i) by (fractional) distillation or accept a description of the distillation process (heat and how separation works) eg heat and condense accept boil / vapourise etc for heat fractionation CO note the order of these products must be correct O wrong way round = mark (b) (i) (hexane) has been broken down (into smaller hydrocarbons / molecules) accept (thermal) decomposition / cracked / split / broken up owtte C C = C accept C = (iii) water / hydrogen oxide / steam accept O Page 57 of 68

58 (c) candidates must include both sugar cane and crude oil in their evaluation and both an advantage and a disadvantage to gain full marks. if they do not then the maximum mark is three any four from: advantages of using sugar country has no wealth to buy (large quantities of) crude oil not expensive alone country has limited technological development or underdeveloped / third world country able / suitable climate to grow sugar cane enough land to grow sugar cane / land cannot be used to grow food / deforestation sugar is a renewable source or crude oil is a non-renewable resource / finite resource / limited resources CO / carbon neutral advantages of using alkanes: economic costs are low continuous process country has large oil resources country has oil refineries / cracking plants very pure product faster process 4 [0] M. (a) (i) poly(ethene) accept polythene (iii) cracking hydrogen Page 58 of 68

59 (b) (i) bar labelled 9 bar drawn to correct height (iii) (boiling point) increases heat / evaporate (the crude oil) accept separate by boiling point cool / condense (hydrocarbons at different temperatures) accept smaller molecules go to top / larger molecules stay at bottom accept fractional distillation for two marks or distillation / fractionation for one mark (c) yes any two from: because plastic does not biodegrade or running out of space for landfills or land cannot be used for a long time it provides heat energy which can be used to generate electricity / heat homes or greenhouses any other advantage of burning any other disadvantage of landfill or no burning plastic produces carbon dioxide / carbon emissions / toxic gases accept landfill does not produce carbon dioxide / carbon emissions causes global warming / climate change / increase greenhouse effect / global dimming / acid rain any other disadvantage of burning any other advantage of landfill [0] Page 59 of 68

60 M3. (a) any two from: asks for cause therefore no marks for just describing the change must link reason to a correct change in a gas carbon dioxide has decreased due to: accept idea of used to indicate a decrease plants / micro organisms / bacteria / vegetation / trees photosynthesis ignore respiration locked up in (sedimentary) rocks / carbonates / fossil fuels dissolved in oceans ignore volcanoes oxygen has increased due to: accept idea of given out / produced plants / bacteria / micro organisms / vegetation / trees photosynthesis ignore respiration nitrogen increased due to: accept idea of given out / produced ammonia reacted with oxygen bacteria / micro organisms ignore (increase in) use of fossil fuels / deforestation (b) (because methane s) boiling point is greater than the average / surface temperature or Titan s (average / surface) temperature is below methane s boiling point ignore references to nitrogen or water any methane that evaporates will condense accept boils for evaporates accept cooling and produce rain for condensing (c) (i) bonds must be displayed correctly ignore bond angles Page 60 of 68

61 poly(propene) / polypropene / polypropylene do not allow polypropane any two from: double bonds open up / break / become single(*) propene molecules / monomers / they join / undergo addition polymerisation(*) form chains / long molecules(*) (*)correct chemical equation gains marks ignore large using monomer incorrectly max marks [8] M4. (a) (i) hydrogen must be name a line of four or more ethene molecules joined to the original two with single bonds at least two other ethene molecules joined to the original two in a chain gains mark (b) (i) any two from: non-biodegradable accept remains a long time landfill sites are filling up / limited accept land / space used up waste of a resource / could be recycled / reused ignore references to tablets / animals any one from: (two) different polymers / plastics / materials need to be separated limited collection points / many need to be collected tablets may still be present [6] Page 6 of 68

62 M5. (a) any two from: naphtha has a different / low(er) boiling point accept different volatility condenses at a different temperature / height / place in the column / when it reaches it s boiling point different size of molecules (b) (i) C 0 C C 4 allow multiples (hydrocarbon) heated / vapours (passed over a) catalyst / alumina / porous pot ignore other catalysts (iii) it / ethene is unsaturated or decane and hexane / they are saturated accept decane and hexane are alkanes / C n n+ or ethene is an alkene / C n n or different homologous series / general formula ethene has a double (carbon carbon) bond or decane and hexane have only single (carbon carbon) bonds accept ethene has a reactive double (carbon carbon) bond for marks (c) all bonds drawn correctly (d) economic argument against recycling any one from: poly(ethene) / plastic must be collected / transported / sorted / washed this uses (fossil) fuels which are expensive Page 6 of 68

63 environmental argument against recycling any one from: uses (fossil) fuels that are non-renewable / form CO / CO / SO / NO x / particulates ignore pollution / harmful gases / etc washing uses / pollutes water counter arguments any two from: collect / transport alongside other waste use biofuels (instead of fossil) landfill is running out landfill destroys habitats incinerators are expensive to build saves raw materials / crude oil saves energy needed to make new plastic incinerators may produce harmful substances incinerator ash goes to landfill poly(ethene) is non-biodegradable poly(ethene) can be made into other useful items more jobs / employment for people [] M6. (a) (i) monomers crude oil Page 63 of 68

64 (b) any three from: metal may not corrode away / remains plastic remains / does not break down (decay) / not affected by microorganisms accept non-biodegradable should recycle / conserve resources / mend the kettle / burn (plastic) as a fuel accept it is a waste of materials / resources landfill sites are limited / filling up water pollution ignore harms wildlife / habitats or problems caused by burning the kettle 3 [5] M7. (a) (i) many ethene / molecules / monomers accept double bonds open / break join to form a long hydrocarbon / chain / large molecule accept addition polymerisation ignore references to ethane correct equation gains marks (can be deformed but) return to their original shape (when heated or cooled) ignore it remembers its shape (iii) cross links / extra bonds in PEX accept inter-molecular bonds ignore inter-molecular forces molecules / chains in PEX are held in position accept rigid structure molecules / chains in PEX unable to slide past each other / move it = PEX throughout Page 64 of 68

65 M8. (a) (i) C 4 (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 [0] poly(ethene) (b) (i) is not biodegradable not enough landfill sites / space accept landfill sites are filling up or plastics remain for years or plastics not broken down ignore cost / waste of resources / not biodegradable / wildlife (iii) less (crude) oil / fuels / energy used accept (crude) oil is a non-renewable resource [5] Page 65 of 68

66 M9. (a) (i) polyethene / poly(ethene) accept polythene / polyethylene needs heat / energy / high temperature / fuel (for cracking) ignore other processes produces carbon dioxide / CO ignore use of CO or produces carbon (b) any three from: use water from local sources or water from close to home recycle bottles in the UK / close to home accept do not recycle in other countries / Asia (reduction in distance travelled) would reduce CO emitted by transport use tap water accept use of transport with low / no carbon dioxide emissions use glass bottles / waxed cartons / metal bottles do not accept do not use plastic bottles without an alternative material do not put in landfill or recycle more reuse / refill plastic bottles tax imported water / plastic bottles (to offset carbon cost) make more / all plastic bottles in UK answers must be about the reduction of carbon cost 3 [6] M30. (a) (i) polyethene / poly(ethene) accept polythene / polyethylene needs heat / energy / high temperature / fuel (for cracking) ignore other processes produces carbon dioxide / CO ignore use of CO or produces carbon Page 66 of 68

67 (b) any three from: use water from local sources or water from close to home recycle bottles in the UK / close to home accept do not recycle in other countries / Asia (reduction in distance travelled) would reduce CO emitted by transport use tap water accept use of transport with low / no carbon dioxide emissions use glass bottles / waxed cartons / metal bottles do not accept do not use plastic bottles without an alternative material do not put in landfill or recycle more reuse / refill plastic bottles tax imported water / plastic bottles (to offset carbon cost) make more / all plastic bottles in UK answers must be about the reduction of carbon cost 3 [6] Page 67 of 68

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