Q1. 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, CH 4 –162 butane, C 4 H 10 0 pentane, C 5 H 12 +36 decane, C 10 H 22 +175 Tick ( ) two statements that are correct about these hydrocarbons. (2) 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 (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) Page 1 of 33
Transcript
Q1. 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, C4H
10
0
pentane, C5H
12
+36
decane, C10
H22
+175
Tick ( ) two statements that are correct about these hydrocarbons.
(2)
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
(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)
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(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.
Q2. A teacher carried out an experiment to study car engine oil. The experiment was carried out in a fume cupboard and the teacher wore plastic gloves. The oil was poured through a funnel. The time taken for all the oil to go through the funnel was measured. The experiment was repeated with the oil at different temperatures.
(a) What two safety precautions were taken in the experiment?
(c) An engine oil must be viscous enough to stop the metal parts of the engine from rubbing against each other. It must not be too viscous or the parts cannot move freely.
(i) Complete the sentences below.
The more viscous a liquid is, the less easily it .......................................... .
As the liquid gets hotter it gets ...................................................... viscous. (2)
(ii) Why should the oil in a car engine not be allowed to get too hot?
Q3. 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.
(1)
(i) The plastic is made from many small molecules called
catalysts
monomers
polymers
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(ii) Propene is produced by cracking some of the fractions that are
(1)
separated from
crude oil
limestone
metal ores
(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.
(c) In this question you will be assessed on using good English, organising information clearly and using specialist terms where apropriate.
There are millions of plastic bags in use. After use most of these plastic bags are buried in landfill sites. The amount sent to landfill could be reduced if the plastic bags: • could be reused • could be recycled by melting and making into new plastic products • could be burned to release energy
Use the information above and your knowledge and understanding to give the positive and negative environmental impacts of using these methods to reduce the amount of plastic bags sent to landfill.
Q10. 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).
Complete the balanced symbol equation by writing in the formulae of the two products.
C2H
5OH + 3O
2 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?
Q13. The diagrams show the percentages of the four main fractions produced from two samples of crude oil, A and B.
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(a) The light fraction contains hydrocarbons used for the manufacture of useful chemicals such as polymers. Which one of the samples, A or B, would be more useful for the manufacture of polymers? Explain your answer.
(c) sulfur dioxide is produced when sulfur burns 1
therefore sulfur must be removed from these fuels because sulfur dioxide causes acid rain
1 [6]
##
(a) fume cupboard plastic gloves (only one tick)
for 1 mark 1
(b) (i) plotting points (allow ± 0.5 units either vertically or horizontally) (all correct = 2) (3 correct =1) curve (not joined with straight lines. Must be very close to all points. One line only) (1 mark)
gains 3 marks 3
(ii) as read from graph (±0.5 units) – points must be joined
for 1 mark 1
(iii) decreases, gets less, quicker for 1 mark
1
(c) (i) flows, moves, passes through (not rubbing/moving of engine parts)
for 1 mark
less etc for 1 mark
2
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(ii) parts rub against each other increases wear of engine parts damages the oil engine seizes overheating of engine (not burns or blows up) (not just ‘damage’)
any 1 for 1 mark 1
[9]
M3. (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]
M4. (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
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(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]
M5. (a) catalyst 1
(b) (i) made up of only carbon and hydrogen 1
(ii) C8H
18
1
(c) (i) ethene 1
(ii) polymerisation 1
[5]
M6. (a) combustion
for one mark 1
(b) B for one mark
1 [2]
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M7. (a) alkanes 1
catalyst 1
substances must be in the order shown
(b) many (ethenes/monomers) 1
bond/join together 1
allow ethenes / monomers bond / join together to form very large molecules for 2 marks
(c) Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response.
No relevant content. 0 marks
There is a brief description of a positive and a negative environmental impact involved with one or more methods used to reduce the amount of plastic bags sent to landfill.
Level 1 (1–2 marks)
There is some description of both positive and negative environmental impacts involved with at least 2 methods used to reduce the amount of plastic bags sent to landfill.
Level 2 (3–4 marks)
There is a clear, balanced and detailed description of both a positive and a negative environmental impact of using each of the 3 methods used to reduce the amount of plastic bags sent to landfill.
Level 3 (5–6 marks)
examples of the chemistry points made in the response
reuse: reuse means less bags used so:
positive environmental impact
• saves raw materials / crude oil
• saves energy
• cuts down on CO2 emissions
• less global warming
negative environmental impact
• could cause litter
• could still be sent to landfill
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recycle: bags bought can be recycled so:
positive environmental impact
• used to make new plastic bags / objects
• saves raw materials / crude oil
• saves energy compared to producing plastic bags from crude oil
• cuts down on CO2 emissions
• less global warming
negative environmental impact
• collection point sites cause an eyesore / litter problem
• transportation to recycling plant releases carbon dioxide / causes global warming
burn: bags can be burned so:
positive environmental impact
• could provide energy for heating buildings
• could provide energy for generating electricity
negative environmental impact
• increases CO2 emissions
• increases global warming
• could release toxic gases
does not conserve raw materials / crude oil [10]
M8. (a) catalyst or speeds up the reaction (owtte)
accept lowers activation energy not just helps reaction to take place ignore increased surface area
1
(b) C8H
18
allow H18C
8
must be upper case do not accept powers
1
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(c) B because it is a gas or because it has small molecules or because they are small
position and reason for mark allow it has a lower / very low boiling point than A ignore references to solubility accept does not condense do not accept light molecules or bubbles into B do not accept it is small
1
(d) breakdown of a substance (owtte) do not accept decompose unqualified
1
by the action of heat (owtte) 1
(e) Quality of written communication
if the written communication makes sense and it is in context then award Q mark Q Q
1
large to small molecules or scientific word that implies smaller, e.g. alkene / ethane / petrol
any name or formula of alkane / alkene smaller than decane 1
either advantages of smaller molecules or disadvantages of larger molecules e.g. hydrocarbons with large molecules are limited in their usefulness
or converse for smaller molecules 1
large hydrocarbon molecules do not ignite easily / do not flow easily / are not very volatile
or converse for smaller molecules
more large hydrocarbon molecules are produced than are needed or converse for smaller molecules
smaller molecules are useful as fuels
alkenes / products can be used to make polymers
(f) (fractional) distillation accept fractionation accept good description do not accept just diagram
1 [9]
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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
(c) any two from:
ignore particles
• (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]
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M10. (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
wrong way round = 1 mark 1
(b) (i) (hexane) has been broken down (into smaller hydrocarbons / molecules) 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]
M11. (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
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(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–CH
2–]
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]
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M12. (a) C2H
4
1
H H H H C C C H H H H
Accept even if in wrong columns 1
(c) (i) polythene or poly(ethene) 1
(ii) addition 1
[4]
M13. (a) B because it contains more of the light fraction) 1
Quantitative answer e.g. B has 30%, A has 20% / 10% more / 1.5 times more
1
(b) (i)
1
(ii) heat 1
catalyst if neither mark gained allow cracking for 1 mark
1 [5]
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M14. (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) C4H
10
1
(b) H H H │ │ │ H ─C ─ C ─ C ─ H │ │ │ H H H
1
(c) (i) C5 to C
8 fraction are fuels or easier to burn or petrol (fraction)
accept C21 to C
24 fraction not useful as fuels
do not accept produce more energy 1
(ii) C2H
4
do not accept C4H
8
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
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