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Unit 1 Mini Mock GCSE Chemistry Higher Tier Questions Q1. The diagram shows an electric light bulb.

When electricity is passed through the tungsten filament it gets very hot and gives out light.

a) What reaction would take place if the hot tungsten was surrounded by air? (1) (b) State why argon is used in the light bulb. Explain your answer in terms of the electronic structure of an argon atom. (3)(Total 4 marks)

Q2. (a) Balance these chemical equations. (i) H2 + O2 → H2O (1) (ii) Al + O2 → Al2O3 (1) (b) Briefly explain why an unbalanced chemical equation cannot fully describe a reaction (2)(Total 4 marks) Q3. Limestone is an important raw material. (a) The main compound in limestone has the formula CaCO3 .Name the elements in this compound. (2) (b) Limestone has many uses. Select from the list below two important materials made from limestone. cement diesel oil glass poly(ethene) sodium hydroxide sulphuric acid (2)

(c) The diagram shows a lime kiln. The limestone is heated by the burning coal.

(i) Suggest why hot air is blown into the lime kiln(1) (ii) Give two reasons why carbon dioxide is produced in the lime kiln. (2) (d) (i) Quicklime (calcium oxide) can be converted to slaked lime (calcium hydroxide) by adding water. Write a word equation to represent this reaction.

.......................... + ........................... → ............................(1) (ii) Why do farmers sometimes add slaked lime to acidic soil? (1) (Total 9 marks)

Q4. Limestone contains calcium carbonate, CaCO3. At a cement works, limestone is mixed with clay and heated in a kiln.

(a) (i) When methane is burned in this process the waste gases contain carbon dioxide and nitrogen. Explain why. (2) (ii) Complete the symbol equation for the thermal decomposition of calcium carbonate.

CaCO3 → ......................... + .........................(2) (b) A different fuel is burnt at the cement works. Suggest one reason the company may give for using this different fuel at the cement works. (1) (c) The cement works continue to burn the different fuel. Local residents are concerned because more children are

suffering asthma attacks. Residents have also noticed that parked cars are becoming dirty because of smoke particles from the chimney. The table shows the possible medical risk from smoke particles.

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It is also recommended that to avoid damage to health, the concentration of any particles should be no higher than 2 parts per million (ppm). Scientists were brought in to monitor the emissions from the cement work’s chimney. They positioned four sensors around the cement works to monitor airborne smoke particles.

These four sensors only detect particle sizes larger than 0.5 mm and measure the concentration of particles in ppm. The scientists reported that the particle sensors showed that the average concentration of particles was 1.8 ppm. The scientists concluded that there was no risk to health. (i)Explain why the local residents objected to the positions of the four sensors. (2) (ii) What evidence did the scientists use to conclude that there was no risk to health? (1) (iii) The local residents were still concerned that there was a risk to health, even though the average concentration of particles was 1.8 ppm.Explain why. (3)(Total 11 marks)

Q5. Magnesium chloride is a useful salt.The flow diagram shows how it can be made.

(i) Describe how calcium hydroxide can be made from limestone. (2) (ii) Write a word equation for the neutralisation of magnesium hydroxide with a suitable acid to form magnesium chloride. (2)(Total 4 marks)

Q6. Copper is found in the Earth’s crust as an ore containing copper sulfide. Large areas of land, where this ore was once quarried, are contaminated with low percentages of copper sulfide. Copper would be too expensive to extract from this contaminated land using the traditional method of quarrying and then heating in a furnace.

(a) The percentage of copper ore in the contaminated land is low. (i) It would be too expensive to extract from this land by the traditional method. Explain why. (1) (ii) Extracting copper from this land by the traditional method would have a major environmental impact.Give one reason why. (1) (b) One way to extract the copper from land that contains low percentages of copper sulfide is by bioleaching. Bioleaching uses bacteria. The bacteria produce a solution of copper sulfate.It is possible to get copper from a solution of copper sulfate using scrap iron. (i) It is economical to use scrap iron to get copper.Give one reason why. (1) (ii) Why can iron be used to get copper from copper sulfate solution? (1) (c) A new way to extract the copper from land that contains low percentages of copper sulfide is phytomining. Phytomining uses plants. Plants are grown on this land and absorb copper compounds through their roots.

(i) Use this information to give two advantages of phytomining compared to the traditional method. (2) (ii) Use this information to suggest one disadvantage of phytomining compared to the traditional method. (1)

(Total 7 marks)

Particle size in mm Medical effect Larger than 0.4 No medical risks known 0.3 and smaller Causes asthma attacks 0.2 and smaller May cause cancer

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Q7. Use the Reactivity Series of Metals on the Data Sheet to help you to answer this question.The table gives information about the extraction of some metals.

(a) Explain why gold is found mainly as the metal itself in the Earth. (1) (b) One of the reactions involved in producing zinc is represented by this equation.

ZnO + C → Zn + CO

Explain why carbon can be used to extract zinc. (1)

(c) Sodium is one of the most abundant metals on

Earth.Explain, as fully as you can, why sodium was not extracted until 1807. (2)(Total 4 marks)

Q8. The demand for iron and steel is high. (a) Iron that is extracted from its oxide by carbon reduction in a blast furnace is called cast iron. Cast iron contains about 4% carbon. This carbon makes cast iron very brittle. Carbon steels can be made by the following processes. • Blowing oxygen into molten cast iron to remove most of the carbon. • Adding a calculated amount of carbon. Sometimes different metals may also be added to the molten carbon steels.

(i) Suggest how blowing oxygen into molten cast iron removes most of the carbon. (2)

(ii) Why are different metals sometimes added to molten carbon steels? (1) (b) The percentage of iron and steel recycled in the UK has been increasing. The UK government has set targets for the percentage of iron and steel to be recycled. In 2006 the target was exceeded. Suggest two reasons why the UK government wants to encourage recycling of iron and steel.(2)(Total 5 marks)

Q9. (a) Some hydrocarbons are used as fuels in power stations.The table gives the boiling points of four hydrocarbons.

i) Which of these hydrocarbons are gases at room temperature (20 °C)? (1)

ii) Which of these hydrocarbons has the largest molecules? (1) iii) Which of these hydrocarbons ignites most easily (1)

(b) Some hydrocarbons are used to produce polymers. Which type of hydrocarbons can be converted into polymers? (1)(Total 4 marks)

Q10. 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(1) (ii) ethene(1) (iii) Give an example of one chemical reaction which both ethane and ethene undergo. (1) (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 ...........................................................(1)(Total 7 marks)

Metal Date of discovery

Main source Main extraction method

Gold Known to ancient civilisations

In the Earth as the metal itself

Physically separating it from the rocks it is mixed with

Zinc 1500 Zinc carbonate

Reduction by carbon

Sodium 1807 Sodium chloride

Electrolysis

Year %iron and steel recycled

1998 25 2000 35 2002 42 2004 46 2006 57

Hydrocarbon Boiling point in °C W 165 X –160 Y –40 Z 180

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Q11. Crude oil is a mixture of mostly alkanes. (a) Crude oil is separated into useful fractions by fractional distillation. (i) Describe and explain how the mixture of alkanes is separated by fractional distillation. (3) (ii) The table gives the name and formula for each of the first three alkanes. Complete the table to show the formula of butane.[1]

(c) The relative amounts of and the market demand for some hydrocarbons from the fractional distillation of crude oil are shown in the graph.

(i) Why is the market demand for the C5 – C8 fraction higher than the market demand for the C21 – C24 fraction?(1) (ii) Cracking is used to break down large hydrocarbon molecules into smaller hydrocarbon molecules. Complete the symbol equation by writing in the formula of the other hydrocarbon. C20H42 à C16H34 + 2 .............................(1) (iii) The C5 – C8 fraction has low supply and high market demand. Suggest three ways in which the oil industry could overcome this problem. (3) (Total 10 marks)

Q12. 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. (1) (b) Name the type of reactions which take place in: (i) REACTOR 1 (ii) REACTOR 2 (2)

(c) The petroleum gases contain ethane, C2H6 and propane, C3H8. (d) Ethane and propane are said to be saturated hydrocarbons. What does saturated mean when used to describe hydrocarbons? (1) (e) Many molecules of ethene join together to form poly(ethene) in REACTOR 2. Complete the diagram below to show the formation of poly(ethene).(2)(Total 7 marks)

Name of alkane Formula Methane CH4

Ethane C2H6

Propane C3H8

Butane

The structural formula of methane, CH4, is shown

b) Draw the structural formula of propane, C3H8(1)

The structure of a molecule of ethane can be represented as:

Draw the structure of a molecule of propane [1]

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Q13. The amount of carbon dioxide in the atmosphere is increased by reactions that occur in internal combustion engines (X) and is decreased by reactions in sea water (Y).

Describe, in as much detail as you can, the reactions which take place at X and Y. (a) X (2) (b) Y (3)(Total 5 marks)

Q14. Since 2000 there has been a lot more research into alternative, environmentally-friendly fuels for road transport.Several pollutants are found in the exhaust emissions produced when fossil fuels are used for road transport.Carbon monoxide (CO) interferes with the way that red blood cells carry oxygen. Carbon dioxide (CO2) increases the level of carbon dioxide in the atmosphere and causes global warming.Oxides of nitrogen (NOx) are produced at high temperatures when nitrogen and oxygen from the atmosphere combine.Sulfur dioxide (SO2) is produced when sulfur impurities in the fuel combine with oxygen in the atmosphere.Tiny particles of solids are produced when the fuel does not burn completely.This increases the level of particulates (PM10) in the atmosphere. (a) Name the environmental effect caused by: (i) oxides of nitrogen (NOx) and sulfur dioxide (SO2)(1) (ii) the increased level of particulates (PM10). (1) (b) Diesel obtained from crude oil is often called fossil diesel. Biodiesel can be made from many vegetable oils. One research project compared the exhaust emissions when fossil diesel or biodiesel were used as fuels. Some of the relative amounts of these exhaust emissions are shown in the bar chart.

(i) Use your knowledge and the information above to explain the environmental benefits of using biodiesel

as a sustainable, low pollution fuel. (3) (ii) Biodiesel is called a green fuel. This is because the life-cycle emission of carbon dioxide from

biodiesel is less than that from fossil diesel.Use your knowledge and the information above to explain why biodiesel’s contribution to global warming is considered to be much less than that of fossil diesel. (3)(Total 8 marks)

Q15. 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) (b) 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? (1) (ii) What type of polymerisation reaction is shown in the equation? (1)(Total 4 marks)

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Q16. This question is about the use hydrocarbons and the production of compounds from hydrocarbons. (a) The equation shows a reaction involving hydrocarbons. C8H18 → C2H4 + C6H14 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.(2) (b) Hydrocarbon J burns completely in oxygen to produce carbon dioxide and water vapour. 2 C8H18 + 25 O2 → 16 CO2 + 18 H2O (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. Answer = ................................. g (2) (ii) The mass of carbon dioxide produced is greater than the 114g of hydrocarbon J that was burned.Explain why.(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.(1) (ii) What advantages to a manufacturer of ethanol, does Process 2 have over Process 1?(2)(Total 11 marks) Q17. 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 100 °C) and ethanol (boiling point 78 °C). (i) How can ethanol be separated from water?(1) (ii) Ethanol, C2H5OH, burns to release heat energy.Complete the balanced symbol equation by writing in the formulae of the two products. C2H5OH + 3O2 à 2......... + 3......... (2) (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? (1) (ii) Complete the structural formula for ethene, C2H4. (1) (iii) Name the compound that is added to ethene to produce ethanol, C2H5OH.(1) (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 10 marks)

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Q18. 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. (1) (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?(1) (ii) Complete the diagram to represent how poly(chloroethene) is formed from chloroethene [3].

(iii) Explain what is meant by the term polymerisation. (2) (iv) Why is this an addition polymerisation? (1)(Total 8 marks) Q19. (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). (2) (ii) PEX is a shape memory polymer. What property does a shape memory polymer have? (1) (iii) The simplified structures of poly(ethene) (structure on left) and PEX (structure on right) are shown.

Poly(ethene) is a thermoplastic that softens easily when heated.Suggest and explain how the structure of PEX changes this property. (3)

(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. (4)(Total 10 marks)

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Q20. (a) The diagrams show the results of shaking a vegetable oil with the substances indicated. (i) Give a reason for the result in Flask 1. (1) (ii) Explain the result in Flask 2. (2) (b) Saturated fats are linked to heart problems. Oils that are unsaturated help to prevent heart disease. A company wants to make a ‘healthy’ soft margarine.The company tested the same volume of different vegetable oils by shaking each with three drops of iodine solution. The results are shown in the table.

(i) Why does iodine react with the molecules in these oils?(1) (ii) Use the company results to evaluate which one appears to be the most ‘healthy’ vegetable oil to use in the soft margarine.(2) (c) The ingredients of soft margarine include hydrogenated vegetable oil. (i) Why is hydrogenated vegetable oil used in soft margarine? (1) (ii) Describe how vegetable oils are hydrogenated.(2)(Total 9 marks)

Q21. An advert for crisps claimed that they are healthier because they are cooked in sunflower oil. (a) A student found the following information about four oils that are used to make crisps.

One hypothesis is that oils are thought to be healthier if they are: • low in saturated fat • high in polyunsaturated fat.

(i) Use the table to decide which oil should be healthiest. Explain your decision by comparing this oil with other oils from the table that you think are less healthy. (2)

(ii) These oils can be hardened by reacting them with hydrogen.A student said that hardening would make sunflower oil healthier.Is this student’s claim correct? Explain your answer.(2) (b) A mixture of the olive oil, water and egg yolk was shaken and left to stand. The olive oil and water do not separate.The diagram shows a simple model of how a stable mixture of olive oil and water is produced by the addition of egg yolk. Use this simple model to explain how the molecules in the egg yolk are able to produce a stable mixture of olive oil and water.(3) (Total 7 marks)

Q22. An advert for some crisps claims that they now contain only 30% saturated fat because they are cooked in sunflower oil. The crisp company used bromine water to compare percentage unsaturation of sunflower oil with four other vegetable oils, A, B, C and D.

(i) What is the range of percentage unsaturation for oils A, B, C and D?(1) (ii) Describe and explain what happens to the first drops of bromine water that are added to these oils.(2) (iii) The average for oil B is given as 23.6 cm3.Explain how this average has been calculated. (1) (iv) The results did not show that sunflower

oil contains 30% saturated fat.Explain why. (You will need to calculate the percentage unsaturation of sunflower oil.)(2)(Total 6 marks)

Vegetable oil Time in minutes for the colour of iodine to ‘disappear’

Olive oil 3.5 Peanut oil 3.0 Soya oil 1.5 Sunflower oil 1.0

Rapeseed oil Sunflower oil Olive oil Corn oil Saturated fat (%) 6.6 12.0 14.3 14.4 Polyunsaturated fat (%) 29.3 63.3 8.2 51.3

Melting point (°C) +5 –18 –12 –15

Oil Volume of bromine water added until the bromine colour just remains (cm3)

Percentage unsaturation (%) Test 1 Test 2 Test 3 Average

Sunflower 25.4 28.0 27.0 26.8 A 13.0 14.0 15.0 14.0 35 B 23.2 11.2 24.0 23.6 59 C 19.9 21.1 20.2 20.4 51 D 9.5 8.8 9.3 9.2 23

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Q23. The diagram below shows a cross-section of a mid-ocean ridge. (a) X and Y are two separate tectonic plates. (i) The two plates are both moving. Explain, as fully as you can, what causes tectonic plates to move.(3) (ii) New ocean floor is created at the mid-ocean ridge. Explain, as fully as you can, how this happens. (3) (b) The layer of sediment that has collected on the ocean floor increases in depth the further it is from the mid-oceanic ridge. Suggest a reason for this. (2)(Total 8 marks) Q24. 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.

Suggest what has caused the main gases in the Earth’s atmosphere of millions of years ago to change to the present-day atmosphere.(2) (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.

When it rains on Titan, it rains methane! Explain why.(2) (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, C3H6, to show the covalent bonds.(1) (ii) Explain how propene molecules form a polymer. You should name the polymer formed.(3)(Total 8 marks)

Q25. For 200 million years the proportions of the different gases in the atmosphere have been much the same as today. Over the past 150 years the amount of carbon dioxide in the atmosphere has increased from 0.03% to 0.04%. (a) Describe how carbon dioxide is released into the atmosphere: (i) by human and industrial activity; (2) (ii) from carbonate rocks by geological activity. (2) (b) Explain how the seas and oceans can decrease the amount of carbon dioxide in the atmosphere. (3) (c) (i) Give one reason why the amount of carbon dioxide in the atmosphere is increasing gradually. (1) (ii) Give one effect that increasing levels of carbon dioxide in the atmosphere may have on the environment.(1) (Total 9 marks)

Mars Earth nitrogen 3% nitrogen 78% oxygen trace oxygen 21% water trace water trace carbon dioxide 95% carbon dioxide trace Average surface temperature –23 °C

Average surface temperature 15 °C

Main gases in Titan’s atmosphere

Percentage (%)

Boiling point in °C

Nitrogen 95 –196 Methane 5 –164 Average surface temperature –178 °C

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Unit 1 Mini Mock GCSE Chemistry Higher Tier ANSWERS M1. (a) react with oxygen / oxidise / burn in oxygen / burning / combustion or tungsten to tungsten oxide or makes an oxide 1 (b) it is (very) unreactive / not reactive / inert / does not react with tungsten or it is a noble gas or it is in group 0 or 8 or 18 1 full outer shell (of electrons) / 8 electrons in outer shell 1 does not need to gain / lose / swap / transfer / share electrons or does not need to form bonds does not bond ionically / covalently 1 [4] M2. (a) (i) H2 + O2 → H2O *both circled correct 1 (ii) A1 + O2 → A12O3 all circled correct 1 (b) idea that: must end up with the same number of atoms as at the start any 2 each otherwise matter is shown to be lost/gained for 1 mark won’t show correct amount of each element/compound 2[4] M3. (a) calcium carbon oxygen 2 (b) cement glass each for 1 mark 2 (c) (i) allows coal to bum / flushes out CO2 1 (ii) produced by burning coal produced by decomposition of limestone 2 (d) (i) calcium oxide + water → calcium hydroxide 1 (ii) to neutralise it / because it is alkaline or basic 1 [9] M4. (a) (i) oxygen / air reacts with carbon / methane (to form carbon dioxide) accept from the decomposition / reaction of calcium carbonate 1 nitrogen is (unreacted) from the air 1 (ii) CaO 1 CO2 1 (b) any one from: • more energy / efficient allow converse for present fuel • from a sustainable / renewable resource • produces less / no carbon dioxide / greenhouse gases / global warming ignore no pollution / environmental damage • more profit or money for local economy accept fuel is cheap(er) • more readily available it = different fuel 1 (c) (i) any two from: • not near where people / residents live accept not between cement works and where people live ignore sensors are unsightly • not positioned where concentration of particles was likely to be highest • not positioned downwind 2 (ii) the average / concentration was 1.8(ppm) or the average / concentration was below 2(ppm) accept 1.8(ppm) is less than 2.0 (ppm) 1 (iii) any three from: • children / people suffering asthma attacks • result was an average • readings (at some (2/3) sensors) could have been higher than 2ppm • sensors did not detect particles below 0.5mm • small particles / particles below 0.5mm / 0.4mm / 0.3mm / 0.2mm could (still) cause cancer / asthma ignore global dimming or cars becoming dirty or position of sensors 3 [11]

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M5. (a) (i) heat (the limestone) accept decompose limestone accept heat with coke 1 add water / slake dependent on 1st mark unless they say add water to the calcium oxide 1 (ii) magnesium hydroxide + hydrochloric acid→ magnesium chloride + water / H2O [4] M6. (a) (i) because large amounts of energy would be needed to extract the copper accept because it is labour-intensive to extract copper from this land accept because copper would have to be extracted from a large area of land 1 (ii) any one from: • produces large amounts of solid waste • atmospheric pollution from carbon dioxide / sulfur dioxide • more lorries / traffic1 (b) (i) iron is cheap accept iron is much more abundant than copper 1 (ii) iron displaces copper from solutions of its salts accept iron is more reactive than copper 1 (c) (i) any two from: • less expensive / energy to extract the small amountsof copper • plants will remove carbon dioxide from the atmosphere as they grow • can release energy when plants are burned 2 (ii) not continuous as it takes a long time for plants to grow accept supply not continuous as plants only harvested once / twice a year 1[7] M7. (a) unreactive / near bottom of reactivity series 1 (b) carbon more reactive / higher up reactivity series 1 (c) very reactive / near top of reactivity series 1 cannot use displacement methods / can only be extracted by electrolysis / had to wait discovery of electricity 1[4] M8. (a) (i) reacts with carbon / C accept burns / oxidises carbon 1 carbon dioxide / CO2 / gas is formed / given off accept carbon monoxide / CO accept correctly balanced equation for 2 marks ignore state symbols 1 (ii) change / improve properties accept any specific property accept to make alloys / special steels ignore brittle 1 (b) any two from: • to conserve ores / iron accept ores / iron are non-renewable / non-sustainable allow less quarrying / mining • to prevent the use of landfills allow reduce waste • to conserve energy / fuel accept fossil fuels are non-renewable • to reduce carbon / carbon dioxide emissions • to meet EU / International targets ignore costs / demand 2[5] M9. (a) (i) X and Y (1) (ii) Z (1) (iii) X (1) (b) unsaturated / alkenes / those with double (C = C) bonds (1) [4] M10. (a) (i)

do not credit CH3CH3 1

(ii) do not credit C2H4 1

(iii) burn or react with oxygen or combustion or oxidation accept react with chlorine 1

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(iv) bubble each gas through (test tube containing) bromine water accept add bromine (water to gas collected) or burn 1 ethene decolourises it or turns the brown colourless accept ethene burns with smoky flame do not accept makes it go clear 1 ethane does not affect it or leaves it brown accept ethane burns with clear flame note carefully the spelling of ethene and ethane 1 (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 1 [7] M11. (a) (i) heat / evaporate the crude oil / change to gas or vapour do not accept heat with catalyst 1 cool / condense (hydrocarbons) allow small molecules at top and / or large molecules at bottom 1 at different temperatures / boiling points if the answer describes cracking ‘ no marks 1 (ii) C4H10 1 (b) H H H H │ │ │ H ─C ─ C ─ C ─ H │ │ │ H H H (c) (i) C5 to C8 fraction are fuels or easier to burn or petrol (fraction) accept C21 to C24 fraction not useful as fuels do not accept produce more energy 1 (ii) C2H4 do not accept C4H8 1 (iii) any three from: • use different / lighter crude oils • develop markets for low demand fractions • develop new techniques / equipment to use low demand fractions as fuels • cracking • convert low demand fractions to high demand fractions or bigger molecules to smaller molecules • develop alternative / bio fuels do not accept price 3 [10] M12. (a) (fractional) distillation/fractionation 1 (b) (i) cracking/decomposition 1 (ii) polymerisation/addition reaction 1

(c)1

d) contains only/all single bonds no double bonds contains maximum number of H atoms carbon atoms bonded to 4 other atoms (not 4 H atoms) will not undergo addition reactions any 1 for 1 mark 1

M13. (a) any two 1 mark each burning / combustion fossil fuels or (locked up) carbon accept fuel / named fuel oxygen used 2 (b) any three from produces (calcium) carbonate which is insoluble produces (calcium) hydrogencarbonate which is soluble photosynthesis releases oxygen 3 [5]

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M14. (a) (i) acid rain accept consequences of acid rain allow asthma / bronchitis ignore toxic gas 1 (ii) global dimming 1 (b) (i) sustainable: maximum two from: • crops (that produce oil) can be grown in most places owtte • renewable • use less fossil fuels / diesel • use (refined) waste oils low pollution: maximum two from: ignore references to CO2 here • most emissions are lower or any two named emissions from CO / SO2 / PM10 are lower • much / lot less SO2 emissions (than the others) owtte • accept spillages / waste is biodegradable • less new CO2 or (more) carbon neutral 3 (ii) plants / photosynthesis use carbon (dioxide) from the air* 1 it / biodiesel releases carbon (dioxide) from plants / crops / photosynthesis* (*) allow 1 mark for biodiesel is (more) carbon neutral 1 (fossil) diesel releases ‘locked up’ / new carbon (dioxide) / doesn’t absorb CO2 / absorbed it millions of years ago 1[8] M15. (a) C2H4 1

Structure of propane (c) (i) polythene or poly(ethene) 1 (ii) addition 1 [4]

M16. (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) 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 2 (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] M17. (a) (i) by (fractional) distillation accept a description of the distillation process (heat and how separation works) eg heat and condense accept boil / vapourise etc for heat or fractionation 1 (ii) CO2 note the order of these products must be correct 1 H2O 1 (b) (i) (hexane) has been broken down (into smaller hydrocarbons / molecules) 1 accept (thermal) decomposition / cracked / split / broken up owtte (ii)

accept CH2 = CH2 1 (iii) water / hydrogen oxide / steam accept H2O 1 (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; CO2 / 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 [10]

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M18. (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 (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–CH2–] 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] M19. (a) (i) many ethene / molecules / monomers accept double bonds open / break 1 join to form a long hydrocarbon / chain / large molecule accept addition polymerization 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 (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] M20. (a) (i) water and oil do not mix / are immiscible ignore density 1 Or don’t dissolve each other ignore emulsifier alone 1 (ii) any two from: • emulsifier • forms an emulsion accept description of an emulsion • holds the two components together accept stops them separating / they mix allow bonds / binds for holds • by lowering the surface tension accept a description of how an emulsifier works for two marks

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eg ‘tadpole’ diagram or dispersal of oil drops 2 (b) (i) (because they contain) a double (carbon carbon) bond accept unsaturated 1 (ii) results suggest sunflower oil is best or ‘the one that took the least time’ 1 because (sunflower oil) has the highest amount of unsaturation / most double bonds / least saturated ignore uses up I2 most quickly second mark is dependent on first 1 (c) (i) any one from: • have a higher melting point than (vegetable) oil • are solid at (room temperature) / hardened / harder accept useful as spreads or doesn’t soak into bread ignore hard / soft(er) 1 (ii) any two from: • hydrogen added do not accept ‘water’ • to carbon carbon double bond / to saturate • (nickel) catalyst / temperature 60 – 150 °C wrong catalyst doesn’t get this mark 2 [9] M21. (a) (i) (healthiest oil is) sunflower (oil) or rapeseed (oil) sunflower (oil) is healthiest because it has less saturated fat than both olive (oil) and corn (oil) or rapeseed (oil) is healthiest because it has the lowest value of saturated fat compared with the other oils 1 sunflower (oil) is healthiest because it has the highest value of polyunsaturated fat compared with all the other oils or rapeseed (oil) is healthiest because it has more polyunsaturated fat than both olive (oil) and corn (oil) 1 (ii) no, because hydrogen adds to the unsaturated fat or no, because hydrogen reduces the number of carbon–carbon double bonds accept no because reacting with hydrogen increases number of single bonds 1 therefore there will be less polyunsaturated fat accept therefore there will be more saturated fat 1 (b) molecules in egg yolk act as emulsifiers accept lecithin molecules act as emulsifiers 1 because molecules in egg yolk have a ‘head’ which dissolves in / attracted to water accept because molecules in egg yolk are hydrophilic 1 because molecules in egg yolk have a ‘tail’ which dissolves in / attracted to oil accept because molecules in egg yolk are hydrophobic 1 [7] M22. (i) 23 to 59 accept 36 1 (ii) decolourise or (orange to) colourless ignore discolours / fades do not allow oil decolourises 1 (because bromine reacts with the) (carbon) double bond ignore alkenes or reference to unsaturation 1 (iii) any one from: • an anomalous result (11.2) / Test 2

accept (= 23.6) • 11.2 / Test 2 is ignored when averaging accept average of tests 1 and 3 1 (iv) unsaturation 67% average was less than it should be / only 26.8 cm3 1 (this means there is) 33% saturated fat it should have been 28.0 cm3 to give a percentage of 70% 1 [6] M23. (a) (i) convection currents in the mantle (1) driven by heat (1) from radioactive processes (1) 3 (ii) plates moving apart magma rises to fill gap forms new rock each for 1 mark 3 (b) Rock further from ridge is older more time for sediment to settle each for 1 mark 2 [8] M24. (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’

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• 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 2 (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 1 any methane that evaporates will condense accept boils for evaporates accept cooling and produce rain for condensing 1 (c) (i)

bonds must be displayed correctly ignore bond angles 1 (ii) 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(*) 1 • form chains / long molecules(*) (*)correct chemical equation gains 2 marks ignore large [8] M25. (a) (i) burning / breathing / respiration / fuels / food for 1 mark each 2 (ii)

1. Rock is heated / subducted (owtte) / close to magma / melted 2. Rock is decomposed / carbon dioxide released through volcanoes 2

(b) carbon dioxide reacts / dissolves in sea-water / dissolves in rain water insoluble carbonates / calcium carbonate are / is formed carbon dioxide turned into shells / coral / limestone / chalk / sediments also soluble hydrogencarbonates (calcium / magnesium) are formed photosynthesis by plants any three for 1 mark each 3 (c) (i) sea unable to absorb all the extra carbon dioxide being produced more trees being cut down / deforestation increased burning of fuels / more cars / more industry (not more people) any one for 1 mark 1 (ii) global warming / greenhouse effect or effects such as melting ice caps / rising sea levels / climatic change / more deserts (not changes to ozone layer) for one mark 1 [9]