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 34
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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, C5H12
+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)
Page 1 of 34
(c) There are two substances produced when natural gas burns with the air hole open.
The diagram shows the Bunsen burner flame when natural gas burns with the airhole closed. Partial combustion takes place.
Name one other substance that could be produced when natural gas burns with the air hole closed.
(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)
Q8. The hydrocarbons in crude oil can be separated into useful fractions.
(a) Why does gasoline (petrol) have a lower boiling point than fuel oil?
Use the correct words from the box to complete the sentences.
bond carbon compound element mixture
(i) Propane is a ....................................... and is made up of atoms of hydrogen
and ....................................... (2)
(ii) Each line between the atoms in propane represents a chemical ....................... (1)
(Total 5 marks)
Q10. Most electricity in the UK is generated in power stations that burn fossil fuels. The diagram lists some of the substances released into the air when fossil fuels are burned.
(a) (i) Which one of the substances released into the air causes acid rain?
(b) The table shows the percentage of electricity generated by different energy sources.
Complete the bar chart to show the percentage of electricity generated by coal and by gas and oil.
(2)
(Total 6 marks)
Energy sources
Renewables Nuclear Coal Gas and Oil
Percentage (%)
8 20 32 40
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Q11. A large reservoir is surrounded by trees. Planners need to protect the environment. The distance around the reservoir is many kilometres. There will be only one road access to a car park a few kilometres from the reservoir. From the car park people would be transported to accommodation, activities or places of interest by steam train.
(a) Coal contains carbon and small amounts of sulfur. The steam train would cause environmental problems if coal were used as the fuel.
(b) The planners have stated that, as a result of using the steam train, there must be no overall increase of carbon dioxide added to the atmosphere. The steam train would be considered as ‘carbon neutral’ if wood, from the surrounding forest, were used as the fuel.
(b) Diesel obtained from crude oil is often called fossil diesel. Biodiesel can be made from many vegetable oils. One research project compared the exhaust emissions when fossil diesel or biodiesel were used as fuels.
Some of the relative amounts of these exhaust emissions are shown in the bar chart.
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(i) Use your knowledge and the information above to explain the environmental benefits of using biodiesel as a sustainable, low pollution fuel.
This is because the life-cycle emission of carbon dioxide from biodiesel is less than that from fossil diesel.
Use your knowledge and the information above to explain why biodiesel’s contribution to global warming is considered to be much less than that of fossil diesel.
Q15. 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?
M2. (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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M3. (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]
M4. (a) combustion
for one mark 1
(b) B for one mark
1 [2]
M5. (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
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(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
OR
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]
M6. (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
Page 24 of 34
(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
3 [10]
M7. (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
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(c)
all three correct = 3 marks two correct = 2 marks one correct = 1 mark
3 [6]
M8. (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
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(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]
M9. (a) (i) made up of one sort of atom
accept it is in the periodic table or has its own symbol
1
(ii) nitrogen / N / N2 or oxygen / O / O
2
do not accept argon or helium do not accept oxide
1
Page 27 of 34
(b) (i) compound 1
carbon 1
(ii) bond 1
[5]
M10. (a) (i) sulfur dioxide / SO2
1
(ii) global dimming 1
(iii) carbon dioxide / CO2
ignore ozone 1
increases the levels (of carbon dioxide) accept it is a greenhouse gas or causes global warming / greenhouse effect
1
(b) gas / oil bar correct length 1
coal bar correct length 1
[6]
Page 28 of 34
M11. (a) any two environmental problems with linked explanations
• global warming (1) accept effects of global warming
caused by (formation of) carbon dioxide / greenhouse gas (1) ignore greenhouse effect
(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