(I) the Coal Is Reacting with When It Burns

COMBUSTION

Q5. The gases produced when coal burns are cooled by ice and then bubbled through limewater.

(a) Complete these sentences.

(i) The coal is reacting with ...... when it burns.

(ii) During burning, elements in the coal are converted to compounds

called ...... (2)

(b) Choose words from this list to complete the sentences.

carbon carbon dioxide sulphur sulphur dioxide

sodium water

(i) Liquid X is a compound made from hydrogen and oxygen.

It is called ......

(ii) Sulphur dioxide is an acidic gas. It is given off when coal burns, because coal

contains the element ......

(iii) Most fuels are compounds of hydrogen and ...... (3) (c) Burning coal is an exothermic reaction.

Explain what “exothermic” means.

......

...... (1)

(d) (i) Which gas turns limewater cloudy?

......

(ii) Which element in the coal is oxidised to form this gas?

...... (2) (Total 8 marks)

Q8. Hot air balloons are used mainly for pleasure trips.

(a) Air is a mixture of gases. Complete the table. (Carbon dioxide has been done for you.)

Gas Chemical formula % in air nitrogen 78

oxygen O2 argon 0.9

carbon dioxide CO2 0.03 (3)

(b) The air in the balloon is heated using a propane burner. Propane, C3H8, is a hydrocarbon

that burns in air forming carbon dioxide, CO2, and water, H2O.

(i) What does hydrocarbon mean?

......

...... (1)

(ii) Which gas, in the air, reacts with propane when it burns?

...... (1)

(iii) What type of chemical reaction happens when a hydrocarbon burns?

...... (1)

(iv) The formation of more carbon dioxide causes global problems. Explain why.

......

...... (2) (Total 8 marks)

Q31. Read the information and then answer the questions.

Cobalt chloride paper can be used to test for water.

The paper contains anhydrous cobalt chloride.

The jar containing the papers must be kept closed when not being used.

The equation shows the reaction between anhydrous cobalt chloride and water.

CoCl2 + 6 H2O CoCl2.6H2O

anhydrous cobalt chloride hydrated cobalt chloride

(blue) (pink)

(a) Choose one word from the box to complete the sentence.

endothermic exothermic reversible

The symbol means that the reaction is ...... (1)

(b) Describe the colour change when water is added to the cobalt chloride paper.

......

...... (1)

......

...... (1) (Total 3 marks)

Q23. Useful fuels can be produced from crude oil. Crude oil is a mixture of hydrocarbons.

(a) The table shows the boiling points of four of these hydrocarbons.

Hydrocarbon Boiling point in °C

methane, CH4 –162 butane, C4H10 0

pentane, C5H12 +36

decane, C10H22 +175

Tick ( ) two statements that are correct about these hydrocarbons.

Statement Tick ( ) decane has the largest molecules pentane is a liquid at 40°C methane and butane are gases at 20°C methane has the highest boiling point butane does not boil

(2)

(b) Natural gas supplied to homes and schools is mainly methane. The diagram shows an apparatus to investigate the two substances produced when natural gas burns completely in air.

(i) Name the liquid that collects in the U-tube...... (1)

(ii) Name the gas that turns the limewater cloudy ...... (1) (c) Some crude oil contains sulfur. Petrol and diesel fuels are produced from crude oil.

The sulfur must be removed from these fuels before they are burned.

Explain why.

......

...... (2) (Total 6 marks)

Q26. In the future more coal-fired and fewer oil-fired power stations will be used to generate electricity. When coal and oil are burned they produce the same types of emissions which can cause environmental problems.

(a) Emissions from the chimney can cause acid rain, global dimming and global warming. Draw one straight line from each possible environmental problem to the emission that causes it. Possible environmental problem Emission that causes it

carbon particles

acid rain

carbon dioxide

global warming

sulfur dioxide

global dimming

water vapour

...... (3)

(b) Draw a ring around the correct word in the box to complete each sentence. carbon dioxide.

(i) Incomplete combustion of coal or oil is caused by too little nitrogen.

oxygen.

(1)

carbon monoxide.

(ii) A gas formed by the incomplete combustion of coal or oil is hydrogen.

oxygen.

(1)

The world production figures after 2000 are predicted. Year World production of coal World production of oil (billions of tonnes per year) (billions of barrels per year)

2000 3.5 12.5

2050 4.5 5.6

2100 5.0 1.7

2150 5.5 0.5

2200 6.0 0.0

(i) How is the world production of oil predicted to change from 2000 to 2200?

......

...... (1)

(ii) Suggest two reasons why the world production of coal is predicted to increase.

1 ......

...... 2 ......

...... (2) (Total 8 marks)

FRACTIONAL DISTILLATION

Q24. To make crude oil more useful it is separated into different fractions.

(a) Complete the gaps in the following sentences.

Crude oil is separated into different fractions by a process called ......

...... Each fraction has a different ...... (2)

(b) Each fraction is a mixture of compounds. Most of these compounds are hydrocarbons, made up of the elements hydrogen and carbon.

(i) Explain the difference between a mixture and a compound.

......

...... (2) (ii) Explain the difference between a compound and an element.

......

...... (2) (Total 6 marks)

Q2. (a) Complete this sentence about crude oil.

Crude oil is mainly a mixture of compounds called ...... which contain carbon and hydrogen only. (1)

(b) The diagram shows a laboratory experiment used to separate crude oil.

Complete each sentence by choosing the correct words from the box. condensation distillation evaporation

melting sublimation

The main process taking place at A is ......

The main process taking place at B is ......

This method of separating crude oil is called ...... (3) (c) Complete this sentence by crossing out the word in each box that is wrong. The first one has been done for you.

This method of separating crude oil works because the the molecules are,

the their boiling point and the volatile they are. (1) (Total 5 marks)

Q4. Crude oil is a natural resource from which useful fuels can be separated.

(a) Crude oil is a mixture of hydrocarbons.

Complete the sentence about a hydrocarbon molecule.

A hydrocarbon molecule is made up of ...... and carbon atoms only. (1)

(b) Many fuels come from crude oil. Some of these fuels are shown in the diagram.

Suggest two properties of these fuels that allow them to be separated from crude oil.

......

...... (2)

(c) Fuels from crude oil burn to provide heat energy. When a fuel burns, it combines with oxygen in the air and produces carbon dioxide and water. When there is not enough oxygen, the fuel burns and also produces carbon monoxide and carbon particles.

Draw a straight line from each substance that links it to a possible environmental problem.

One has been done for you.

(3) (Total 6 marks)

Q5. 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.

Name of alkane Formula

Methane CH4

Ethane C2H6

Propane C3H8

Butane

(1)

(b) The structural formula of methane, CH4, is:

H │ H  C  H │ H

Draw the structural formula of propane, C3H8 (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 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.

1 ......

......

2 ......

......

3 ......

...... (3) (Total 10 marks)

Q9. The hydrocarbons in crude oil can be separated into useful fractions.

Carbon Boiling point Relative % Relative % Fraction chain in °C in crude oil demand length

Naphtha 20–180 5–9 10 20

Gasoline (petrol) 20–200 5–10 10 20

Kerosene 180–260 10–16 15 23 (paraffin)

Diesel 260–340 14–20 20 25

Fuel oil 370–600 20–70 45 12

(a) Why does gasoline (petrol) have a lower boiling point than fuel oil?

......

...... (1)

(b) Suggest why gasoline (petrol) costs more than fuel oil.

......

...... (2)

......

...... (2) (Total 5 marks)

Q19. Crude oil is a resource from which fuels can be separated.

(a) The name of the main fuel fractions and one of the hydrocarbons in each fraction are shown in the table.

(i) How does the number of carbon atoms in a hydrocarbon affect its boiling point?

......

...... (1)

(ii) Suggest the lowest temperature to which crude oil needs to be heated to vaporize all the hydrocarbons in the table.

Temperature = ...... °C (1)

(iii) Dodecane boils at 216 °C. At what temperature will dodecane gas condense to liquid?

Temperature = ...... °C (1)

(b) The bar chart shows the relative supply and demand for the petrol and diesel fractions. (i) How does the relative supply and demand for petrol and diesel fractions cause problems for an oil company?

......

...... (2)

(ii) Suggest one way an oil company could solve these problems.

......

...... (1) (Total 6 marks)

CRACKING

Q31. 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?

......

...... (1) (b) What is the chemical formula of the molecule shown above?

...... (1)

(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?

......

...... (2)

(ii) What effect does the porous pot catalyst have on the reaction?

......

...... (1)

(iii) Complete the equation below for the cracking of the molecule. C20H42.

C20H42 → C12H26 + ...... (1) (Total 6 marks)

Q6. The structural formulae of two saturated hydrocarbons are shown below. Describe two ways in which they will differ in their physical properties.

1 ......

......

2 ......

...... (Total 2 marks)

Q7. 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.

......

...... (2) (b) Why is compound A useful in industry?

......

...... (1) (Total 3 marks)

Q12. 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?

...... (1)

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

...... (1)

Compound Y is unsaturated. Compound Z is saturated.

(i) Suggest one use for compound Y.

...... (1)

(ii) Suggest one use for compound Z.

...... (1) (Total 4 marks)

Q30. 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?

......

...... (1)

(b) What is the chemical formula of the molecule shown above?

...... (1)

(i) What happens during thermal decomposition?

......

...... (2) (ii) What effect does the porous pot catalyst have on the reaction?

......

...... (1)

(iii) Complete the equation below for the cracking of the molecule. C20H42.

C20H42 → C12H26 + ...... (1) (Total 6 marks)

Q33. 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 (C4H10), a hydrocarbon in crude oil, can be cracked to produce two different hydrocarbons, ethane

(C2.4) and ethene (C2H4)

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

......

...... (2)

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

(2)

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

...... C2.4(g) + ...... (g) → ...... (g) + ...... (l) (3)

(b) The second stage is the formation of the plastic material by polymerisation. Describe how ethene (C2H4) forms poly(ethene). You do not need to give the reaction conditions or the names of catalysts.

......

...... (3) (Total 10 marks)

ETHANOL

Q3. 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 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.

C C (1)

(iii) Name the compound that is added to ethene to produce ethanol, C2H5OH.

...... (1)

Evaluate the advantages and disadvantages of using these two starting materials to produce ethanol.

......

...... (4) (Total 10 marks)

Q21. 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)

Process 1 Process 2

Fermentation of a sugar solution by Reaction of ethene (from crude oil) with yeast in a reaction vessel. steam in a reactor.

The reaction vessel has to be emptied, The reaction is only stopped if there is a cleaned and refilled every few days. fault in the reactor.

The process produces a 15% ethanol The process produces 100% ethanol. solution in water.

(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)

ADDITION POLYMERS

Q29. Propane and ethene are both important hydrocarbons.

(a) Complete the table by adding the formula of the ethene molecule and the structure of the propane molecule. (2)

(c) Ethene can be changed into a plastic. The equation shown below represents the reaction in which ethene is polymerised. (i) What is the name of the plastic formed in this reaction?

...... (1)

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

...... (1) (Total 4 marks)

Q1.

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)

Q10. Tablet containers are often made from two different polymers.

(a) Ethene, C2H4, and propene, C3H6, 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. (1)

(ii) Ethene molecules are used to form poly(ethene) molecules.

Complete the diagram to show the poly(ethene) molecule.

Ethene molecules Poly(ethene) molecule

(2)

(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.

1 ......

......

2 ......

...... (2)

(ii) Suggest one reason why recycling the tablet containers would be difficult.

......

...... (1) (Total 6 marks)

Q15. 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.

catalysts

(i) The plastic is made from many small molecules called monomers

polymers

(1)

(ii) Propene is produced by cracking some of the fractions that are

crude oil separated from limestone

metal ores

(1)

(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.

1 ......

......

2 ......

......

3 ......

...... (3) (Total 5 marks)

Q18. Crude oil is used to make useful substances such as alkenes and plastics.

(a) The alkene shown is ethene.

(i) Tick ( ) the correct formula for ethene.

Formula ( )

CH4

C2H4

C2H6

(1)

(ii) Tick ( ) the name of the plastic formed when many ethene molecules join together.

Name of plastic ( )

Poly(ethene)

Poly(ethanol)

Poly(propene)

(1)

(b) Read the article about plastics and then answer the questions.

THE PROBLEM WITH 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

decomposes because it is flammable . is not biodegradable

(1)

(ii) Suggest a problem caused by 80% of the plastics going to landfill sites.

......

...... (1)

(iii) The UK government has set a target to recycle 30% of plastic waste.

How are resources saved by recycling more plastics?

......

...... (1) (Total 5 marks)

Q28. Crude oil is used to make plastics.

(a) To make a plastic from crude oil involves many processes.

(i) How do alkene molecules form a molecule of a plastic?

......

...... (1)

(ii) Suggest one of the main costs of making a plastic from crude oil.

......

...... (1) (iii) Suggest two problems caused by the disposal of plastics in landfill sites.

1 ......

......

2 ......

...... (2)

(b) Some companies are using bio-plastics made from plants such as corn. Less fossil fuel is used to make bio-plastics than is used to make plastics from crude oil.

Plastics made from plants would be more environmentally friendly than plastics made from crude oil.

Explain why.

......

...... (2) (Total 6 marks)

Q8. 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.

(2)

(b) Saturated hydrocarbons, such as propane, are fuels.

Write a balanced equation for the complete combustion of propane, C3H8.

...... + ...... → ...... + ...... (3) (Total 5 marks)

EXTRACTION OF METALS

Q3. A student was trying to extract the metals from lead oxide and aluminium oxide.

She heated each oxide with carbon in a fume cupboard as shown below.

She was able to extract lead from lead oxide but not aluminium from aluminium oxide.

(i) Explain the results of these experiments.

......

(ii) Complete this word equation for the reaction between lead oxide and carbon.

lead oxide + carbon → ...... + ...... (Total 5 marks)

Q4. Part of a reactivity series is:

(a) Carbon is used in blast furnaces to obtain iron and zinc from their oxides, but electrolysis has to be used to obtain aluminium from its oxide.

Draw an arrow on the reactivity series above to show where carbon fits into the series. (1)

(b) Predict the method of extraction used to obtain calcium from its ore and explain your answer.

......

...... (2)

...... (2) (Total 5 marks)

Q6. 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.

Metal Date of discovery Main source Main extraction method

Gold Known to ancient In the Earth as the Physically separating it civilisations metal itself from the rocks it is mixed with

Zinc 1500 Zinc carbonate Reduction by carbon Sodium 1807 Sodium chloride Electrolysis

(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)

Explain, as fully as you can, why sodium was not extracted until 1807.

......

...... (2) (Total 4 marks)

M6. (a) unreactive / near bottom of reactivity series 1

(b) carbon more reactive / higher up reactivity series 1

cannot use displacement methods / can only be extracted by electrolysis / had to wait discovery of electricity 1 [4]

Q11. The reaction between aluminium and iron oxide is used to weld together railway lines.

2Al(s) + Fe2O3(s) → 2Fe(l) + Al2O3(s)

A simple, qualitative energy level diagram for this reaction is shown.

Use the energy level diagram to:

(i) describe the idea of activation energy;

......

...... (1)

(ii) explain why the reaction produces molten iron.

......

...... (2) (Total 3 marks)

Q16. A student investigated the electrolysis of lead bromide.

Lead bromide was placed in the tube and the circuit was switched on. The light bulb did not light up.

The tube was heated and soon the bulb lit up. The observations are shown in the table.

Positive electrode Negative electrode

red-brown gas silver liquid

(a) What is meant by electrolysis?

...... (2)

(b) Why did the lead bromide conduct electricity when the tube was heated?

...... (1)

positive electrode; ......

negative electrode...... (2) (d) Suggest one safety precaution that should be taken during this investigation.

...... (1) (Total 6 marks)

COMBUSTION MS

M5. (a) (i) oxygen (not air)

(ii) oxides/monoxides/dioxides for 1 mark each

Do not allow specific examples 2

(b) (i) water

(ii) sulphur

(iii) carbon for 1 mark each 3

(d) (i) carbon dioxide

(ii) carbon for 1 mark each

(allow correct symbols/formulae) 2 [8]

M8. (a) N2 1

20–21% accept an answer in this range 1

Ar 1 (b) (i) compound of carbon and hydrogen only do not accept ‘mixture’ 1

(ii) Oxygen or O2 1

(iii) exothermic accept combustion or oxidation 1

(iv) increases greenhouse effect 1

global warming or example 1 [8]

M31. (a) reversible 1

(b) (from blue) to pink do not accept incorrect initial colour 1

• stop water reaching papers accept stop entry of moisture / wet / dampness / condensation

• water (vapour) in air ignore references to toxicity of cobalt chloride 1 [3]

M23. (a) decane has the largest molecules 1

methane and butane are gases at 20 °C 1

(b) (i) water 1

(ii) carbon dioxide 1

therefore sulfur must be removed from these fuels because sulfur dioxide causes acid rain 1 [6]

M26. (a) acid rain → sulfur dioxide 1

global warming → carbon dioxide 1

global dimming → carbon particles 1

(b) (i) oxygen 1

(ii) carbon monoxide 1

(ii) any two from: it = coal

• world needs (more) energy accept population is increasing allow (greater) demand for coal / fuels / energy

• plentiful supply accept readily available allow coal will ‘last longer’

• (many) countries have coal

• easy to find / extract

• oil / gas is running out accept need to use less oil / gas accept need to use it to replace oil / gas • cheap or cheaper than oil 2 [8]

FRACTIONAL DISTILLATION MS

M24. (a) fractional distillation 1

boiling point or use 1

(b) (i) mixture: compounds or elements or substances together but not chemically combined ignore references to separation 1

compound: (different) elements or different atoms together and chemically combined ignore references to separation 1

(ii) element: contains only one type of atom accept made of atoms which contain the same number of protons 1

compound: contains different types of atom chemically combined ‘chemically combined’ not needed here if already stated in (b)(i) 1 [6]

M2. (a) hydrocarbons 1

(b) evaporation 1

condensation 1

distillation allow fractional distillation 1 (c) lower and more 1 [5]

M4. (a) hydrogen ignore formulae 1

(b) any two from:

• different sized molecules / more or less (carbon) atoms (in molecules) ignore different densities

• fuels have different boiling points

• fuels condense at different temperatures 2

(c)

all three correct = 3 marks two correct = 2 marks one correct = 1 mark 3 [6]

M5. (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 ─C ─ C ─ C ─ H │ │ │ H H H 1

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]

M9. (a) any one from: • gasoline / petrol / it contains short(er) chains / hydrocarbons or small(er) molecules or contains few(er) carbons accept fuel oil contains long(er) chain length / large(r) molecules or contains many carbons ignore particles

• gasoline / petrol / it has weak(er) / small(er) intermolecular forces accept fuel oil has strong(er) / great(er) intermolecular forces 1

(b) only accept figures if used in a comparative statement

any two from:

• gasoline / petrol / it is in high demand accept fuel oil is in low demand

• gasoline / petrol / it is in short supply accept fuel oil is plentiful accept answers such as ‘gasoline / petrol / its supply is less than demand for 2 marks or gasoline / petrol / its percentage in crude oil is less than demand for 2 marks

• (high) tax / duty

• cracking costs in terms of money / energy accept cracking expensive 2

• (fuel oil / it) heated / vaporised

• with catalyst accept a named catalyst if first two bullet points are not awarded ‘cracking’ gains 1 mark

• (to give / form / produce) short(er) chains / hydrocarbons or small(er) molecules or contains few(er) carbons if wrong process named max 1 mark 2 [5]

M19. (a) (i) the greater the number (of carbon atoms), the higher its boiling point do not accept hydrocarbons for carbon atoms allow converse allow melting point 1

(ii) accept answers in the range 344 to 350 1

(iii) 216 1

(b) (i) EITHER

shortage of petrol or demand for petrol is higher than supply

diesel is in excess or supply of diesel is higher than demand 1

petrol low supply and diesel high supply (1)

petrol high demand and diesel low demand (1) petrol / diesel not specified = max 1 1

(ii) any one from:

• use diesel to make petrol accept crack diesel or description of cracking

• make diesel cheap(er) (than petrol) or make petrol more expensive accept lobby the government to reduce the tax on diesel / increase tax on petrol

• mix ethanol with petrol ignore biodiesel 1 [6]

CRACKING MS

M31. (a) A compound made from carbon and hydrogen (not mixture etc.) 1

(b) C5H12 1 (e) (i) Break down

by heat

(ii) Speeds up reaction

(iii) C8H16 each for 1 mark 4 [6]

M6. B will have higher melting point higher boiling point be less volatile be more viscous (allow less flammable) any two for 1 mark each [2]

(a) Compound A has fewer C atoms or Compound B has fewer H atoms

Compound A has C = C/double bond or Compound A is unsaturated each for 1 mark (accept converse i.e compound B has not ...) 2

(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 1 mark 1 [3]

(a) Compound A has fewer C atoms or Compound B has fewer H atoms

Compound A has C = C/double bond or Compound A is unsaturated each for 1 mark (accept converse i.e compound B has not ...) 2 (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 1 mark 1 [3]

M12. (a) hydrocarbon 1

(b) thermal decomposition / cracking 1

(ii) fuel 1 [4]

M30. (a) A compound made from carbon and hydrogen (not mixture etc.) 1

(b) C5H12 1

(e) (i) Break down

by heat

(ii) Speeds up reaction

(iii) C8H16 each for 1 mark 4 [6]

M33. (a) (i) heat accept increase temperature ignore pressure 1

with a catalyst 1

(ii) 1

accept displayed formulae only 1

(iii) O2 1

CO2 + H2O ignore state symbols 1

correct balancing 2 + 7 → 4 + 6

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

(b) double bond breaks 1

many (ethene) molecules accept many monomers 1

bond together accept join or combine for bond accept

for first 2 marks ignore unsaturated becomes saturated 1 [10]

ETHANOL MS

M3. (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

fractionation 1

(ii) CO2 note the order of these products must be correct 1

H2O wrong way round = 1 mark 1

(b) (i) (hexane) has been broken down (into smaller hydrocarbons / molecules) 1 accept (thermal) decomposition / cracked / split / broken up owtte

(ii) H H │ │ C = C │ │ H H

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

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]

M21. (a) (i) thermal decomposition 1

(ii) hydration 1

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

K will decolourise these solutions or L will not decolourise these solutions 1

(b) (i) 352 (g) for correct answer if answer is incorrect 400 + 114 – 162 gains 1 mark 2

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

because 2 molecules of hydrocarbon J produced 16 molecules of carbon dioxide allow because oxygen has been added to hydrocarbon J for 1 mark 2

(ii) alcohol does not need to be distilled accept alcohol produced is pure 1

process is continuous 1 [11]

ADDITION POLYMERS MS

M29. (a) C2H4 1

H H H H C C C H H H H Accept even if in wrong columns 1

(ii) addition 1 [4]

M1. (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)

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]

M10. (a) (i) hydrogen must be name 1

(ii) 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 1 mark 2

(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 2

(ii) 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 1 [6]

M15. (a) (i) monomers 1

(ii) crude oil 1 (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]

M18. (a) (i) C2H4 1

(ii) poly(ethene) 1

(b) (i) is not biodegradable 1

(ii) 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 1

(iii) less (crude) oil / fuels / energy used accept (crude) oil is a non-renewable resource 1 [5]

M28. (a) (i) any one from:

• bond / join (together) ignore polymerisation / heat

• double bond opens 1

(ii) any one from:

• heat / energy ignore many processes / distillation / cracking / polymerisation

• cost of fuels / the crude oil • construction of the factory / plant

• wages / salaries 1

(iii) any two from: ignore gases released / burning / habitats

• 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 accept crude oil is running out 2

(b) any two from:

• renewable / sustainable ignore recycling ignore crude oil is running out

• less fuel burned accept less energy / heat needed

• biodegradable

• natural resource

• plants absorb carbon dioxide 2 [6] EXTRACTION OF METALS MS

M3. (i) idea that: carbon is above lead in the reactivity series } NOT for 1 mark

carbon is below aluminium in the reactivity series } OXIDE for 1 mark

carbon can remove oxygen from/reduce lead oxide or cannot remove oxygen from aluminium oxide not aluminium more reactive than lead for 1 mark

OR similar ideas in comparing bond strengths 3 (ii) (carbon + lead oxide) →*lead + *carbon dioxide each for 1 mark

accept correct formulae CO2 and CO NOT carbon oxide 2 [5]

M4. (a) This part was not marked 1

(b) electrolysis 1

because calcium is more reactive (than aluminium or carbon) accept it is more reactive or very reactive 1

in a blast furnace 1

because calcium is less reactive (than carbon or lower) 1

2ZnO + C → 2Zn + CO2

ZnO + CO → Zn + CO2

ZnO + C → Zn + CO 1 [5]

M11. (i) the energy needed by reactants before reaction can occur accept energy required for particles to collide successfully accept energy required to break bonds accept energy needed to start reaction 1 (ii) reference to reactants ‘energy’ higher than products ‘energy’ accept exothermic reaction accept heat (energy) released 1

melting point of iron is exceeded accept temperature is above melting point of iron 1 [3]

M16. (a) breakdown / decomposition / splits into elements / not ions

separates into elements / produce a chemical reaction 1

using electricity 1

(b) lead bromide melted / free ions

not electrolyte 1

(–) lead element must be appropriate to electrode 1

(d) fume cupboard / protective clothing allow safety glasses not safety mat 1 [6]

M19. (a) (i) bulb lights up 1

bubbles / fizz / gas or chlorine given off 1

(ii) in solid, ions 1

are not free to move / (charged) particles cannot move or converse atoms / electrons cannot move worth 0 marks 1

(b) (i) breakdown / decomposition / splitting up not separation 1

by using electricity 1

(ii) gas A = chlorine / oxygen 1

deposit B = copper 1

• manufacturer of chlorine / sodium hydroxide / hydrogen / sodium

• electroplating of steel / reference to plating not galvanising

• extraction of aluminium / metal reactivity series specified

• purification of copper not making copper 1 [9]