(1) (2) - Tasker Milwardscience.taskermilward.org.uk/Mod1/KS4Chemistry/AQA/Module2/AQA … ·...

Q1. The table shows how much carbon dioxide is produced when you transfer the same amount of energy by burning coal, gas and oil.

(a) Use the information from the table to complete the bar-chart. (2)

(b) The second bar-chart shows how much sulphur dioxide is produced by burning the same three fuels.

Compare the amount of sulphur produced by burning gas with the amount produced by burning coal.

.....................................................................................................................................

..................................................................................................................................... (1)

(c) Burning fuels also produces nitrogen oxides, even though the fuels contain no nitrogen. Explain why this happens.

.....................................................................................................................................

..................................................................................................................................... (2)

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(d) When you release the same amount of energy from coal, gas and oil, different amounts of carbon dioxide are produced. Use the information below to explain why.

(3)

(e) What other element do coal and oil usually contain?

..................................................................................................................................... (1)

(Total 9 marks)

Q2. The table shows how much carbon dioxide is produced when you transfer the same amount of energy by burning coal, gas and oil.

(a) Use the information from the table to complete the bar-chart. (3)

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(b) The second bar-chart shows how much sulphur dioxide is produced by burning the same three fuels.

Compare the amount of sulphur produced by burning gas with the amount produced by burning coal.

.....................................................................................................................................

..................................................................................................................................... (2)

(c) (i) Coal and oil produce carbon dioxide and sulphur dioxide when they burn. What elements must they contain?

...........................................................................................................................

........................................................................................................................... (2)

(ii) Burning fuels also produce nitrogen oxides, even though the fuels contain no nitrogen. Explain why this happens.

...........................................................................................................................

........................................................................................................................... (2)

(Total 9 marks)

##

The table gives some information about a family of molecules in crude oil.

NUMBER OF CARBON ATOMS IN MOLECULE

MASS OF MOLECULE (atomic units)

1 16

2 30

4 58

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(a) Show information from the table in the most appropriate way on the grid.

(3)

(b) What is the mass of a molecule with three carbon atoms?

..................................................................................................................................... (1)

(c) The other atoms in each molecule are all hydrogen atoms. What family of substances do all the molecules belong to?

..................................................................................................................................... (1)

(d) The mass of a carbon atom is 12 atomic units. The mass of a hydrogen atom is 1 atomic unit.

So the molecule with one carbon atom has four hydrogen atoms. Its formula is CH

4.

Write down the formula:

(i) of the molecule with two carbon atoms ......................

(ii) of a molecule from the same family with five carbon atoms ...................... (2)

(Total 7 marks)

Q4. Choose words from this list to complete the sentences,

ammonia carbon dioxide hydrogen nitrogen

electrical heat solar sound

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(a) In air, the two most common gases are oxygen and ............................................. .

(b) When natural gas burns, energy is released mainly as .......................................... .

(c) When natural gas burns, a gas is produced which turns limewater milky.

The gas is ......................................................... . (Total 3 marks)

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)

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(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)

Q6. A student is using a spirit burner to heat some water.


Substances like methylated spirit which we burn to give out energy, are called

.................................... . The energy is given out as .................................... energy. (2)

(b) Choose a word from this list to complete the sentence below.

gases liquids solids

The methylated spirit seems to disappear as it burns.

The new substances produced during burning are mainly ......................................... (1)

(Total 3 marks)

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Q7. Natural gas is a fuel.


When the fuel burns completely, we cannot see the new substances produced because

they are mainly colourless ....................................................... .

The energy of the fuel is released as ........................................ . (3)

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

carbon carbon dioxide hydrogen nitrogen

oxygen sulphur dioxide water vapour

Three gases which can be produced when fuels burn are:

1. ...........................................................................................................................

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

3. ........................................................................................................................... (3)

(Total 6 marks)

Q8. The structural formulae of two saturated hydrocarbons are shown below.

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Describe two ways in which they will differ in their physical properties.

1 .................................................................................................................................

....................................................................................................................................

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

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

Q9. Here is the word equation for a chemical reaction.

methane + oxygen → water + carbon dioxide

Write down everything that the word equation tells you about the reaction.

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

...............................................................................................................................................

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

Q10. This experiment shows a candle burning then going out.

(a) Choose words from this list to complete the sentences in parts (i) and (ii) below.

air carbon dioxide hydrogen nitrogen oxygen

(i) When the candle wax is burning it is reacting with ...................................... from

the ................................................... . (2)

(ii) One product of the reaction is ......................................................................... (1)

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(b) Complete the following sentence.

In another experiment a 200 cm3 beaker is used. The candle will then burn

for about ........................................... seconds. (1)

(Total 4 marks)

Q11. In a car engine petrol burns in oxygen from the air. Two of the gases in the exhaust fumes are carbon dioxide and water vapour.

This indicates that petrol contains the elements ............................. and ............................... (Total 2 marks)

Q12. Petrol burns in oxygen from the air in a car engine.

Two of the gases in the exhaust fumes are carbon dioxide and water vapour.

This indicates that petrol contains the elements ............................................ and

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

Q13. Wax is a fuel.

A young child watched a candle burning and wondered where the wax had gone.

(a) Complete the sentence below.

When wax burns, energy is released as ...................................................................... (1)

(b) Why does the wax disappear as it burns?

.....................................................................................................................................

..................................................................................................................................... (1)

(Total 2 marks)

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Q14. Choose words from this list to complete the sentences below.

a chemical an electrical a physical hydrogen nitrogen oxygen

(a) Burning is ................................................................. change. (1)

(b) When substances burn, they are reacting with .................................... from the air. (1)

(Total 2 marks)

Q15. The table shows some of the products which are obtained from the fractional distillation of crude oil.

Fraction Nature of products

A a mixture of gases

B a mixture of low boiling point liquids

C 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 .............................................................................................................................. (2)

B .....................................................................

Use .............................................................................................................................. (2)

C .....................................................................

Use .............................................................................................................................. (2)

(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 ................................................................. (1)

(Total 7 marks)

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Q16. Crude oil and natural gas are mixtures of hydrocarbons. They are obtained from wells drilled into rocks where they are trapped.

(a) (i) What is the name of the process used to separate the different hydrocarbons in crude oil?

........................................................................................................................... (1)

(ii) Methane is one of the gases obtained when crude oil is separated.

Give the name of another hydrocarbon gas obtained from this process.

........................................................................................................................... (1)

(b) A fuel used in gas cookers is natural gas. It is mainly methane, CH4.

(i) Complete the word equation for the complete combustion of methane.

methane + oxygen → .................................... + .............................................. (2)

(ii) What different gas is produced by the incomplete combustion of methane?

......................................................................................................................... (1)

(Total 5 marks)

Q17. 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)

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(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)

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Q18. The table shows the composition of some crude oil.

Fraction Percentage in crude

oil

Gases 3

Petrol 7

Naphtha 10

Kerosine 15

Gas oil 20

Fuel oil 45

(a) Complete the pie chart for the composition of this crude oil. Remember to label the chart.

(3)

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(b) The diagram shows the process of separating a different sample of crude oil into fractions.

(i) What is the name given to this process?

........................................................................................................................... (1)

(ii) Which fraction has the lowest boiling point?

........................................................................................................................... (1)

(iii) Which fraction is the least volatile?

........................................................................................................................... (1)

(Total 6 marks)

Q19. 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).

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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)

Q20. Crude oil is a mixture of hydrocarbons. These hydrocarbons can be separated and some of them can be used to make other useful products.

(a) Complete the sentence.

Hydrocarbons are made up of ................................ atoms and ................................ atoms. (2)

(b) How are the small and large hydrocarbon molecules in crude oil separated?

.....................................................................................................................................

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (2)

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(c) The diagram shows that one useful product of cracking is fuels. Name one of the other useful products.

..................................................................................................................................... (1)

(Total 5 marks)

Q21. Crude oil is separated into fractions by fractional distillation.

The table gives information about some of the fractions.

Fraction Boiling point

range in °C

Number of carbon atoms per molecule

Gas Below 20 1 – 4

Petrol 20 – 100 5 – 10

Paraffin 100 – 250 11 – 15

Diesel 250 – 350 16 – 20

Lubricant 350 – 500 21 – 35

Bitumen Above 500 Above 35

(a) What is the relationship between the boiling point of a fraction and the number of carbon atoms in its molecules?

.....................................................................................................................................

..................................................................................................................................... (1)

(b) Give one further difference, other than boiling point, between diesel and paraffin that also depends on the number of carbon atoms in their molecules.

.....................................................................................................................................

..................................................................................................................................... (1)

(c) All the fractions contain hydrocarbons.

Name the two elements in a hydrocarbon.

............................... and ............................... (1)

(Total 3 marks)

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Q22. Propane has a small, hydrocarbon molecule, so it is used as a fuel.

(a) Complete the sentences by choosing the correct words from the box.

Propane is a hydrocarbon with a .................................... boiling point. Propane is a

hydrocarbon because it is made of .................................. and carbon only. (2)

carbohydrate high hydrogen

hydroxide low volatile

(b) Describe, in as much detail as you can, what happens when propane burns.

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

....................................................................................................................................

.................................................................................................................................... (3)

(Total 5 marks)

Q23. Crude oil contains many different hydrocarbons.

(i) Which formula in the list represents a hydrocarbon? Draw a ring around the correct formula.

CO2 C

6H

12O

6 C

8H

18 H

2O

(1)

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(ii) Which word from the list below best describes crude oil? Draw a ring around the correct word.

alloy compound element mixture (1)

(iii) Choose, from the list below, words to complete the passage about the separation of the hydrocarbons in crude oil by fractional distillation.

atoms burned condensed evaporated filtered

fractions ions molecules neutralised

During fractional distillation the many hydrocarbons in crude oil are separated

into ................................. each of which contains ................................ with a

similar number of carbon .................................... .

To do this the oil is first .................................... and then ....................................

at a number of different temperatures. (5)

(Total 7 marks)

Q24. (a) Burning fuels changes the Earth’s atmosphere. The new substances produced are mainly gases. The following is a list of types of reaction.

combustion cracking electrolysis

fermentation neutralisation reduction

Choose, from the list, the word which has the same meaning as burning.

..................................................................................................................................... (1)

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(b) The table shows the gases formed when four fuels, A to D, are completely burned in air.

Which fuel, A to D, is hydrogen, H2? ...............................

(1) (Total 2 marks)

FUEL GAS FORMED ON BURNING

CARBON DIOXIDE CO

2

WATER VAPOUR H

2O

SULPHUR DIOXIDE SO

2

A

B

C

D

Q25. Crude oil is obtained by drilling into the Earth’s crust. The diagram shows a section through the Earth’s crust to show how this is done.

(a) Crude oil contains many hydrocarbons. Which elements do hydrocarbons contain?

.................................................................................................................................... (1)

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(b) The crude oil is separated by fractional distillation. The diagram shows a column used for this.

(i) Explain, as fully as you can, how fractional distillation works.

............................................................................................................................

............................................................................................................................

............................................................................................................................

............................................................................................................................

............................................................................................................................ (3)

(ii) Naphtha burns more easily than diesel oil. Explain why.

............................................................................................................................

............................................................................................................................

............................................................................................................................ (1)

(iii) Naphtha contains a saturated hydrocarbon with the formula C7H

16 .

Draw the structural formula of this compound.

(2)

(Total 7 marks)

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Q26. (a) Crude oil is a mixture of many compounds. Most of the compounds consist of molecules made only of carbon and hydrogen. Choose one word from the list below to complete the sentence.

carbohydrates carbonates hydrocarbons hydrogencarbonates

Compounds made only of carbon and hydrogen are called ....................................... (1)

(b) The fractions contain molecules with similar numbers of carbon atoms. The main fractions are shown in the table below.

Naphtha burns more easily than diesel oil. Explain why.

.....................................................................................................................................

.....................................................................................................................................

..................................................................................................................................... (1)

(Total 2 marks)

NAME OF FRACTION NUMBER OF CARBON ATOMS IN MOLECULES

petroleum gases

gasoline

naphtha

kerosene

diesel oil

lubricating oil

residue

1 to 4

4 to 12

7 to 14

11 to 15

14 to 19

18 to 30

more than 30

Q27. Crude oil is a complex mixture of hydrocarbons, mainly alkanes. The number of carbon atoms in the molecules ranges from 1 to over 100.

(a) How does the boiling point change as the number of carbon atoms in the molecules increases?

.....................................................................................................................................

..................................................................................................................................... (1)

(b) Name the method used to separate petroleum into fractions.

..................................................................................................................................... (1)

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(c) The simplest hydrocarbon is methane, CH4. Its structure can be represented:

Draw the structure of ethane, C2H

6.

(1) (Total 3 marks)

Q28. The diagram below shows a camping stove used by some students.

A student wrote the report below to explain how the stove works. The report has had some words removed. Complete the report using words from the list.

air chemical change liquids physical change

argon gases nitrogen solid

carbon dioxide heat energy oxygen water vapour

To use the stove a fuel called methylated spirits is poured into the burner and lit with a match.

The holes in the base let .................................... into the stove. This contains the gas called

...................................... which is needed for the fuel to burn.

When the fuel burns, new substances are formed. This shows that a .............................

takes place.

When all of the methylated spirits has burned nothing is left in the burner. This shows that

the new substances must all be .................................... .

Methylated spirits contains carbon and hydrogen. When the fuel burns the carbon is changed

into .................................................... .

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The hydrogen is changed into .................................................... .

When the fuel burns it gives out .................................... which cooks the food in the pan. (Total 7 marks)

Q29. Crude oil is a mixture of many saturated hydrocarbons. They can be separated into fractions by the process of fractional distillation.

State what is meant by:

(i) hydrocarbon. ............................................................................................................

.................................................................................................................................... (2)

(ii) saturated. ..................................................................................................................

.................................................................................................................................... (1)

(iii) fraction. ....................................................................................................................

.................................................................................................................................... (1)

(Total 4 marks)

Q30. Crude oil is a mixture of many saturated hydrocarbons. They can be separated into fractions by the process of fractional distillation.

State what is meant by:

(i) hydrocarbon. ............................................................................................................

.................................................................................................................................... (2)

(ii) saturated. ..................................................................................................................

.................................................................................................................................... (1)

(iii) fraction. ....................................................................................................................

.................................................................................................................................... (1)

(Total 4 marks)

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M1. (a) both bars correct height (to better than half a square)

1 mark for both

both bars correctly labelled (w.r.t. relative heights if these incorrect)

for 1 mark 2

(b) a lot less / much less / 18 times less (converse must specify coal) gains 1 mark

1

(c) ideas that

• at high temperatures (produced when fuels burn)

• nitrogen and oxygen from air / atmosphere combine / react or nitrogen from air / atmosphere oxidises

for 1 mark each 2

(d) ideas that

• coal produces most carbon dioxide / more CO2 than gas / oil

• because coal is (mostly) carbon

• gas produces less carbon dioxide than coal / oil

• oil and gas also contain hydrogen / contain more hydrogen atoms than carbon atoms / also produce water

any three for 1 mark each 3

(e) sulphur for 1 mark

2 [9]

M2. (a) each bar correct height (2 bars) to less than ½ square

1 mark for each

both bars correctly labelled (in relation to size of bars) for 1 mark

3

(b) less gains 1 mark

but a lot less / much less / 18 times less or more if referring to coal

gains 2 marks 2

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(c) (i) carbon sulphur

for 1 mark each 2

(ii) ideas that

• at high temperatures, (produced when fuels burn)

• nitrogen and oxygen from atmosphere combine / react for 1 mark each

2 [9]

M3. (a) • vertical axis appropriately scaled

[i.e. using more than half the grid]

• all three points correctly plotted* (to < ½ a square)

• reasonably straight line drawn through points (to < half a square)* [*credit both these marks for bars correctly drawn since discontinuous variable]

each • for 1 mark

x [If points incorrectly plotted credit 1 mark for the best fit straight line or curve but not point-to-point]

3

(b) 44 (atomic units) for 1 mark (e.c.f. i.e. credit consistent with candidate’s graph)

1

(c) hydrocarbons / alkanes for 1 mark

1

(d) C2H

6

C5H

12

each for 1 mark

[NB figures must be subscripted] 2

[7]

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M4. (a) nitrogen / N2

[Do not allow N or N2] for 1 mark

(b) heat for 1 mark

(c) carbon dioxide / CO2

for 1 mark [3]

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

(c) gives out/releases heat/energy for 1 mark

1

(d) (i) carbon dioxide

(ii) carbon for 1 mark each

(allow correct symbols/formulae) 2

[8]

M6. (a) fuels heat – allow light

for 1 mark each 2

(b) gases for 1 mark

1 [3]

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M7. (a) substances/chemicals/compounds

gains 1 mark

but gases (accept vapours) gains 2 marks

heat (accept light) for 1 mark

3

(b) carbon dioxide/CO2

water (vapour)/H2O

sulphur dioxide/SO2

(accept correct formulae) in any order for 1 mark each

3 [6]

M8. 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]

M9. idea of react/reactant/burn/combine idea of produce/product/formed/make (NOT a chemical symbol equation) methane + oxygen identified as reactants carbon dioxide + water identified as products

each for 1 mark [4]

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M10. (a) (i) oxygen air

each for 1 mark 2

(ii) carbon dioxide for 1 mark

1

(b) 30 seconds 5 inclusive for 1 mark

1 [4]

##

carbon; hydrogen (any order)

each for 1 mark [2]

##

hydrogen carbon

in any order each for 1 mark [2]

M13. (a) heat/light 1

(b) any reference to the products being (colourless) gases/smoke 1

[2]

M14. (a) a chemical 1

(b) oxygen 1

[2]

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M15. (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 fuel or making ethene for polymerisation

propane bottled or camping gas or fuel

accept relevant trade names e.g. Calor Gas 2

butane bottled or camping gas or fuel or lighter fuel

B any pair from

petrol or gasoline fuel for cars

accept car engines do not credit just cars

naptha petrol or chemicals or feedstock or solvent

paraffin or kerosene heating fuel or aviation fuel

accept jet or aircraft fuel 2

C any pair from

naptha petrol or chemicals or feedstock or solvent

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paraffin or kerosene heating fuel or aviation fuel

diesel or diesel oil or (light) gas oil 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

2

(b) CO2 and H

2O

both required 1

[7]

M16. (a) (i) fractional distillation

both words required accept fractionation

1

(ii) any one from

ethane

propane

butane 1

(b) (i) carbon dioxide 1

water (vapour) accept steam do not credit symbols

1

(ii) carbon monoxide accept CO do not credit soot or carbon oxide

1 [5]

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M17. (a) (i)

do not credit CH

3CH

3

1

(ii)

do not credit C

2H

4

1

(iii) burn or react with oxygen or combustion or oxidation

accept react with chlorine 1

(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]

M18. (a) all plots correct

3 or 2 plots correct gains 1 mark 2

all sectors correctly labelled 1

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(b) (i) (fractional) distillation 1

(ii) gases 1

(iii) bitumen 1

[6]

M19. (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]

M20. (a) carbon 1

hydrogen any order

1

(b) fractional 1

distillation accept description • heat or evaporate / boil (1mark) • separated when they condense or by boiling points (1 mark)

1

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(c) alkenes accept names or unsaturated hydrocarbons

1 [5]

M21. (a) the higher the boiling point, the greater the number of carbon atoms 1

(b) volatility / viscosity / runnyness / flammability / smokiness / amount of oxygen needed for burning / melting point

do not credit how heavy it is / how it burns 1

(c) hydrogen and carbon (both) allow H and C (upper case)

1 [3]

M22. (a) low 1

hydrogen 1

(b) any three from

• flame accept it is a blue / yellow colour

• reacts with oxygen accept burns in oxygen / bonds broken

• carbon dioxide carbon monoxide forms accept CO

2 arco / bonds forming in CO

2/CO and H

2O

bonds forming 1 mark max accept an oxide of hydrogen or H

2O

• water (vapour) forms accept heat or light released / temperature increase / exothermic

• energy released 3

[5]

M23. (i) C8H

18

for one mark 1

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(ii) mixture for one mark

1

(iii) fractions molecules atoms evaporated condensed

in this order for 1 mark each 5

[7]

M24. (a) combustion

for one mark 1

(b) B for one mark

1 [2]

M25. (a) hydrogen and carbon

for 1 mark 1

(b) (i) the oil is evaporated / boiled / liquid converted to gas / vaporised

oil is condensed/changed back to liquid/cooled below boiling point (not just cooled)

liquids of different boiling points condense at different levels / fractions with lower boiling points form near the top / boiling point linked to chain length or Mr

each for 1 mark 3

(ii) Assume they mean naphtha unless they say otherwise. smaller molecules /contains less atoms /lower boiling point /more volatile /less bonds to break /lower activation energy

If the answer is given the opposite way around then diesel must be specified.

any one for 1 mark 1

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(iii)

correct number of atoms = 1 correct number of bonds (attached to correct atoms) = 1 Accept diagrams which show electrons correctly. CH

3CH

2CH

2CH

2CH

2CH

2CH

3 = 1

for 2 marks 2

[7]

M26. (a) hydrocarbons

for 1 mark 1

(b) less carbon atoms / smaller molecule for 1 mark

1 [2]

M27. (a) the more C atoms the higher the b.pt./temperature Allow just higher. Not answer based on melting point

for 1 mark 1

(b) (fractional) distillation/fractionation for 1 mark

1

(c)

must include H atoms and lines not CH3 – CH

3

for 1 mark 1

[3]

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M28. air/gases oxygen O

2

chemical change/reaction gases carbon dioxide/CO

2

water [vapour] H2O

(heat or heat energy or energy) for 1 mark each

[7]

M29. (i) carbon and hydrogen only or compound of

for 1 mark each 2

(ii) single bonds only or no double bonds etc or contains maximum number of hydrogen atoms

for 1 mark 1

(iii) molecules of similar chain length similar boiling points limited range of boiling points etc

any 1 for 1 mark 1

[4]

M30. (i) carbon and hydrogen only or compound of

for 1 mark each 2

(ii) single bonds only or no double bonds etc or contains maximum number of hydrogen atoms

for 1 mark 1

(iii) molecules of similar chain length similar boiling points limited range of boiling points etc

any 1 for 1 mark 1

[4]

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