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C1.5 Useful products from crude oil Revision Higher
Q1. 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.
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(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)
Q2. The diagram shows an apparatus that can be used to carry out cracking reactions in a laboratory.
(a) Why is aluminium oxide or broken porcelain used?
..................................................................................................................................... (1)
(b) Paraffin contains decane. The cracking of decane can be represented by the equation below. A decane molecule is split into two smaller molecules.
Complete the equation by adding the formula of the other product.
C10H22 (l) →.................... (l) + C2H4 (g) decane
(1)
(c) Would you expect C2H4 molecules to collect at position A or B shown on the diagram?
Position ............................
Explain your answer.
..................................................................................................................................... (1)
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(d) Cracking reactions involve thermal decomposition.
What is meant by thermal decomposition?
.....................................................................................................................................
..................................................................................................................................... (2)
(e) Explain, as fully as you can, why cracking is used in the oil industry.
To gain full marks in this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
..................................................................................................................................... (3)
(f) The cracking reaction produces a mixture of products. The mixture contains hydrocarbons with different boiling points.
Suggest a method of separating this mixture.
.....................................................................................................................................
..................................................................................................................................... (1)
(Total 9 marks)
Q3. Crude oil is a mixture of many compounds. The diagram below shows some of the processes that take place in a petrochemical plant.
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(a) Name the process which takes place in the COLUMN.
..................................................................................................................................... (1)
(b) Name the type of reactions which take place in:
(i) REACTOR 1 ..............................................................................................
(ii) REACTOR 2 .............................................................................................. (2)
(c) The petroleum gases contain ethane, C2H6 and propane, C3H8.
The structure of a molecule of ethane can be represented as:
ethane
Draw the structure of a molecule of propane in the space below.
propane
(1)
(d) Ethane and propane are said to be saturated hydrocarbons. What does saturated mean when used to describe hydrocarbons?
(1)
(e) Many molecules of ethene join together to form poly(ethene) in REACTOR 2.
Complete the diagram below to show the formation of poly(ethene).
(2)
(Total 7 marks)
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Q4. Most plastic bags are made from poly(ethene).
Poly(ethene) is a polymer made from ethene.
Ethene is made by cracking saturated hydrocarbons from crude oil.
(a) Use words from the box to complete the sentences about cracking.
alkanes alkenes catalyst fuel gas
Cracking involves heating the .......................................... to make a vapour.
The vapour is either passed over a hot ............................................... or mixed
with steam and heated to a very high temperature so that thermal decomposition
reactions happen. (2)
(b) Poly(ethene) molecules are made from ethene molecules by a polymerisation reaction.
Describe what happens in a polymerisation reaction.
........................................................................................................................
........................................................................................................................
........................................................................................................................ (2)
(c) 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.
........................................................................................................................
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........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................ (6)
(Total 10 marks)
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Q5. The label has been taken from a tube of Humbrol Polystyrene Cement, a glue used in model making.
(a) The solvent used is 1,1,1-trichloroethane. The structural formula of this molecule is:
(i) What do the lines between the atoms represent?
........................................................................................................................... (1)
(ii) State whether 1,1,1-trichloroethane is saturated or unsaturated. Give one reason for your answer.
...........................................................................................................................
...........................................................................................................................
........................................................................................................................... (1)
(iii) 1,1,1-trichloroethane is being replaced in favour of a ‘better’ solvent. Use information on the label to help you to suggest why.
...........................................................................................................................
........................................................................................................................... (1)
(b) Polystyrene is a plastic. Plastics are polymers which are made by the process of polymerisation.
(i) What is meant by polymerisation?
...........................................................................................................................
........................................................................................................................... (2)
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(ii) The table gives information about monomers and the polymers made from them. Complete the table.
(3)
(Total 8 marks)
Q6. 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)
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(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)
(c) As explained in parts (a) and (b), ethanol can be made using either sugar or alkanes as the starting material.
Evaluate the advantages and disadvantages of using these two starting materials to produce ethanol.
....................................................................................................................................
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....................................................................................................................................
....................................................................................................................................
....................................................................................................................................
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....................................................................................................................................
.................................................................................................................................... (4)
(Total 10 marks)
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C1.6 Plant oils and their uses Revision Higher
Q1. An advert for crisps claims that they now contain only 30% saturated fat because they are cooked in sunflower oil.
(a) The oil is extracted from sunflower seeds. The diagram shows how this can be done.
Draw a ring around the correct word in each box to complete the sentences.
(i)
evaporating.
The oil is obtained from crushed sunflower seeds by filtering.
pressing.
(1)
(ii)
burn
The oil does not dissolve in water.
melt
(1)
(b) Draw a ring around the correct word in the box to complete the sentence.
Carbon carbon double bonds in sunflower oil can be detected
bromine.
by reacting with iron.
oxygen.
(1)
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(c) Water has a boiling point of 100 °C. Sunflower oil has a boiling point above 232 °C.
Suggest why sunflower oil and not water is used to make crisps from thin slices of potato.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
..................................................................................................................................... (2)
(Total 5 marks)
Q2. Many plants produce useful oils.
(a) The diagram shows some apparatus used to obtain oil from plant material.
Four parts of the apparatus are labelled, A, B, C and D.
Use the information in the diagram to complete the sentences.
Steam is made in part .
Oil from the plant material is vaporised in part .
Steam and oil vapour are condensed in part . (3)
(b) A student investigated a mixture of a plant oil and water.
(i) A mixture of the plant oil and water was shaken and left to stand for 10 minutes.
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Draw a ring around the correct answer to complete the sentence.
dissolves.
floats.
sinks.
The plant oil separates from the water because it
(1)
(ii) A mixture of the plant oil, water and egg yolk was shaken and left to stand for 10 minutes. The mixture did not separate.
Draw a ring around the correct answer to complete the sentence.
a compound.
an emulsion.
a fat.
The plant oil, water and egg yolk make
(1) (Total 5 marks)
Q3. Use the correct words from the box to complete the sentences.
higher hydrogen lower
oxygen saturated unsaturated
(i) Animal and vegetable oils that contain .................................. fats can be hardened. (1)
(ii) When oils are hardened with .................................. gas, a chemical change takes
place, producing margarine which has a .................................. melting point than
the original oil. (2)
(Total 3 marks)
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Q4. This information was taken from a label on a packet of crisps.
Main ingredients:
Potatoes, vegetable oil, Worcester sauce flavour,
colourings, flavourings, salt.
Nutritional information (per 100 g):
Energy 2040 kJ
Protein 6.5 g
Carbohydrate 55 g
of which sugars 3 g
Fat 27 g
of which saturates 9 g
unsaturates 18 g
Fibre 4.5 g
Sodium 1.2 g
Saturated fats are linked to heart problems. In order to claim that their crisps are healthy, the manufacturer keeps the proportion of saturated fats low.
(i) What type of fat contains double carbon carbon bonds?
..................................................................................................................................... (1)
(ii) The colour of bromine water is orange.
What is seen when bromine water is shaken with:
an unsaturated fat ........................................................................................................
a saturated fat? ............................................................................................................ (2)
(iii) Unsaturated vegetable oils can be hardened to make them useful as spreads. Describe how unsaturated vegetable oils are hardened.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
..................................................................................................................................... (2)
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Q5. (a) The diagrams show the results of shaking a vegetable oil with the substances indicated.
(i) Give a reason for the result in Flask 1.
..........................................................................................................................
.......................................................................................................................... (1)
(ii) Explain the result in Flask 2.
..........................................................................................................................
..........................................................................................................................
.......................................................................................................................... (2)
(b) Saturated fats are linked to heart problems. Oils that are unsaturated help to prevent heart disease. A company wants to make a ‘healthy’ soft margarine.
The company tested the same volume of different vegetable oils by shaking each with three drops of iodine solution. The results are shown in the table.
Vegetable oil Time in minutes for the
colour of iodine to ‘disappear’
Olive oil 3.5
Peanut oil 3.0
Soya oil 1.5
Sunflower oil 1.0
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(i) Why does iodine react with the molecules in these oils?
..........................................................................................................................
.......................................................................................................................... (1)
(ii) Use the company results to evaluate which one appears to be the most ‘healthy’ vegetable oil to use in the soft margarine.
..........................................................................................................................
..........................................................................................................................
.......................................................................................................................... (2)
(c) The ingredients of soft margarine include hydrogenated vegetable oil.
(i) Why is hydrogenated vegetable oil used in soft margarine?
..........................................................................................................................
.......................................................................................................................... (1)
(ii) Describe how vegetable oils are hydrogenated.
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..........................................................................................................................
.......................................................................................................................... (2)
(Total 9 marks)
Q6. An advert for crisps claimed that they are healthier because they are cooked in sunflower oil.
(a) A student found the following information about four oils that are used to make crisps.
Rapeseed oil Sunflower oil Olive oil Corn oil
Saturated fat (%) 6.6 12.0 14.3 14.4
Polyunsaturated fat (%)
29.3 63.3 8.2 51.3
Melting point (°C) +5 –18 –12 –15
One hypothesis is that oils are thought to be healthier if they are: • low in saturated fat
• high in polyunsaturated fat.
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(i) Use the table to decide which oil should be healthiest. Explain your decision by comparing this oil with other oils from the table that you think are less healthy.
Healthiest oil is .....................................................................................
Explanation ...........................................................................................
...............................................................................................................
............................................................................................................... (2)
(ii) These oils can be hardened by reacting them with hydrogen. A student said that hardening would make sunflower oil healthier. Is this student’s claim correct?
Explain your answer.
...............................................................................................................
...............................................................................................................
............................................................................................................... (2)
(b) A mixture of the olive oil, water and egg yolk was shaken and left to stand. The olive oil and water do not separate.
The diagram shows a simple model of how a stable mixture of olive oil and water is produced by the addition of egg yolk.
Use this simple model to explain how the molecules in the egg yolk are able to produce a stable mixture of olive oil and water.
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................ (3)
(Total 7 marks)
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Q7. An advert for some crisps claims that they now contain only 30% saturated fat because they are cooked in sunflower oil. The crisp company used bromine water to compare percentage unsaturation of sunflower oil with four other vegetable oils, A, B, C and D.
Oil
Volume of bromine water added until the bromine colour just remains (cm3)
Percentage unsaturation
(%) Test 1 Test 2 Test 3 Average
Sunflower 25.4 28.0 27.0 26.8
A 13.0 14.0 15.0 14.0 35
B 23.2 11.2 24.0 23.6 59
C 19.9 21.1 20.2 20.4 51
D 9.5 8.8 9.3 9.2 23
(i) What is the range of percentage unsaturation for oils A, B, C and D?
Range = ................................................ % (1)
(ii) Describe and explain what happens to the first drops of bromine water that are added to these oils.
.....................................................................................................................................
.....................................................................................................................................
..................................................................................................................................... (2)
(iii) The average for oil B is given as 23.6 cm3.
Explain how this average has been calculated.
.....................................................................................................................................
..................................................................................................................................... (1)
(iv) The results did not show that sunflower oil contains 30% saturated fat.
Explain why. (You will need to calculate the percentage unsaturation of sunflower oil.)
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..................................................................................................................................... (2)
(Total 6 marks
C1.7 Changes in the Earth and it’s
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atmosphere Revision Higher
Q1. The diagram represents a section through the Earth showing the layers which are labelled A, B, C and D.
(a) Give the name of:
(i) layer A .............................................................................................................
(ii) layer B ............................................................................................................. (2)
(b) Give one difference between layer C and layer D.
....................................................................................................................................
.................................................................................................................................... (1)
(Total 3 marks)
Q2. A map of the world shows that the outline of South America looks as if it would fit into the west coast of Africa.
• Alfred Wegener in 1920 suggested his idea that the continents had been joined together but then slowly drifted apart.
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• Other scientists in 1920 said that the continents were fixed on solid Earth and had been joined by a land bridge.
Modern South American animals are different from modern African animals.
Most fossils of animals found in South America and Africa are exactly the same.
(a) Consider the information above.
(i) What evidence gave Wegener the idea that the continents of South America and Africa had been joined?
..........................................................................................................................
.......................................................................................................................... (1)
(ii) Suggest two reasons why the other scientists in 1920 thought that Wegener was wrong.
1 .......................................................................................................................
..........................................................................................................................
2 .......................................................................................................................
.......................................................................................................................... (2)
(b) Complete the sentences by writing in the correct words.
Recent evidence has supported Wegener’s idea.
The Earth’s .................................. and the upper part of the mantle are now thought to
be composed of tectonic plates.
Heat released by radioactive processes causes convection currents within the Earth’s
.................................. These convection currents cause the plates to move a few
centimetres per ................................... (3)
(Total 6 marks)
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Q3. (a) The diagram shows the layered structure of the Earth.
(i) Write in the boxes the name of layer X and the name of layer Y. (2)
(ii) The overall density of the Earth is about 5500 kg/m3. The average density of the rocks in the Earth’s crust is about 2800 kg/m3. What does this suggest about the material that makes up the lower layers of the Earth?
..........................................................................................................................
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..........................................................................................................................
.......................................................................................................................... (2)
(b) In 1915, the scientist Alfred Wegener suggested that Africa and South America had once been joined but had since drifted apart. Evidence for his theory came from the animal fossils found in the two continents. The fossils are almost the same, although animals now living in Africa and South America are different. Other scientists did not agree with Wegener and suggested that a land bridge had once joined the two continents.
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How could scientists use the idea of a land bridge to explain the evidence put forward by Wegener?
.....................................................................................................................................
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..................................................................................................................................... (2)
(c) Scientists now think that the outer layer of the Earth is cracked into a number of large pieces called tectonic plates. The tectonic plates are moving very slowly. The lines on the diagram show the boundaries between the major tectonic plates.
(i) Explain why there are no major earthquakes in Britain.
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.......................................................................................................................... (2)
(ii) What is causing the tectonic plates to move?
..........................................................................................................................
.......................................................................................................................... (1)
(Total 9 marks)
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Q4. The diagram shows a view of the inside of the Earth.
Adapted from Physics for You (1996) by Keith Johnson, Nelson Thornes
(a) The curved lines marked X show two of the slow currents in the mantle.
(i) What sort of currents are these?
.......................................................................................................................... (1)
(ii) How do these currents occur and what is their energy source?
..........................................................................................................................
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..........................................................................................................................
.......................................................................................................................... (3)
(b) Movements of the plates of the Earth’s crust can result in earthquakes.
Give two other geological results of these movements.
1 ..................................................................................................................................
2 .................................................................................................................................. (2)
(Total 6 marks)
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Q5. Billions of years ago, the Earth’s early atmosphere was probably like the atmosphere of Venus today.
The table shows a comparison of the atmospheres of the Earth and Venus today.
Percentage composition of atmosphere
Name of gas Earth today Venus today
Nitrogen 78 3.5
Oxygen 21 a trace
Argon 0.97 a trace
Carbon dioxide 0.03 96.5
Average surface temperature 20 ºC 460 ºC
(a) Use the names of gases from the table to complete the sentences.
(i) In the Earth’s atmosphere today, the main gas is .................................................. . (1)
(ii) In the Earth’s atmosphere billions of years ago, the main gas was
............................................................ . (1)
(b) (i) Scientists do not know the accurate composition of the Earth’s early atmosphere. Suggest why.
...........................................................................................................................
........................................................................................................................... (1)
(ii) Use information from the table to answer this question.
Water vapour is present in the atmospheres of the Earth and Venus today. The Earth’s surface is mainly covered by water.
Suggest why there is no water on the surface of Venus.
...........................................................................................................................
........................................................................................................................... (1)
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(c) The diagram shows how carbon dioxide is removed from the Earth’s atmosphere.
Describe what happened to the carbon dioxide in the Earth’s early atmosphere. Use the diagram to help you.
.....................................................................................................................................
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.....................................................................................................................................
..................................................................................................................................... (3)
(Total 7 marks)
Q6. (a) During the first billion years of the Earth’s existence, there were many active volcanoes. The volcanoes released the gases that formed the early atmosphere.
Describe how volcanoes caused the oceans to be formed.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
..................................................................................................................................... (2)
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(b) The atmosphere on Earth today is very different from the early atmosphere.
The pie chart shows the amounts of different gases in the air today. Choose gases from the box to label the pie chart.
argon carbon dioxide hydrogen nitrogen oxygen
(2)
(Total 4 marks)
Q7. For 200 million years the proportions of the different gases in the atmosphere have been much the same as today. Over the past 150 years the amount of carbon dioxide in the atmosphere has increased from 0.03% to 0.04%.
(a) Describe how carbon dioxide is released into the atmosphere:
(i) by human and industrial activity;
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
........................................................................................................................... (2)
(ii) from carbonate rocks by geological activity.
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........................................................................................................................... (2)
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(b) Explain how the seas and oceans can decrease the amount of carbon dioxide in the atmosphere.
.....................................................................................................................................
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.....................................................................................................................................
..................................................................................................................................... (3)
(c) (i) Give one reason why the amount of carbon dioxide in the atmosphere is increasing gradually.
...........................................................................................................................
........................................................................................................................... (1)
(ii) Give one effect that increasing levels of carbon dioxide in the atmosphere may have on the environment.
........................................................................................................................... (1)
(Total 9 marks)
Q8. Air is a mixture of gases and contains various pollutants. The gases are useful and can be separated by fractional distillation of liquid air. The table gives information about some of the gases in air.
Name of gas Formula Melting point in °C Boiling point in °C
Helium He –272.2 –269.0
Oxygen O2 –219.0 –183.0
Nitrogen N2 –210.0 –195.9
Argon Ar –189.0 –185.9
Carbon dioxide CO2 –78.5 –78.5
Water vapour H2O 0.0 100.0
To separate these gases:
• the air is filtered • water is removed first • carbon dioxide is then removed by absorption • the gases remaining are compressed and cooled to –200 °C.
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(a) The air is filtered before the gases are separated.
Suggest why.
........................................................................................................................
........................................................................................................................ (1)
(b) Water vapour and carbon dioxide are removed before the gases are compressed and cooled.
Use the information in the table to suggest why.
........................................................................................................................
........................................................................................................................
........................................................................................................................
........................................................................................................................ (2)
(c) After the water and carbon dioxide have been removed, which gas stays liquid over the greatest temperature range?
........................................................................................................................ (1)
(d) After the water and carbon dioxide have been removed, the four gases that are left are compressed and cooled to –200 °C.
(i) Which gas does not liquefy?
............................................................................................................... (1)
(ii) The three liquefied gases are then allowed to warm up.
Give the order in which the three liquefied gases would vaporise.
1st ...................................................
2nd ..................................................
3rd ................................................... (1)
(Total 6 marks)
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C1.5 Answers
M1. (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
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]
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M2. (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) C8H18
allow H18C8
must be upper case do not accept powers
1
(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
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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]
M3. (a) (fractional) distillation/fractionation
for 1 mark 1
(b) (i) cracking/decomposition
for 1 mark 1
(ii) polymerisation/addition reaction
for 1 mark 1
(c)
(Must have H atoms)
for 1 mark 1
(d) contains only/all single bonds no double bonds contains maximum number of H atoms carbon atoms bonded to 4 other atoms (not 4 H atoms) will not undergo addition reactions
any 1 for 1 mark 1
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(e) (n must be on (right))
= 2 marks
(n on left = 1 mark)
= 2 marks
= 1 mark
= 1 mark
(Double bond loses both marks)
= 0 marks
OR
= 2 marks
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(for both a minimum of 4 carbon atoms)
= 1 mark
= 2 marks
= 1 mark
= 1 mark 2
[7]
M4. (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
Page 32
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
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
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• 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]
M5.(a) (i) bonds / pair of electrons / shared electrons
for one mark 1
(ii) saturated since it has single bonds / no double bonds / no multiple bonds / maximum number of atoms attached
for one mark 1
(iii) sensible answer (e.g. it is harmful) or better solvent could be used on expanded polystyrene or foam
for one mark 1
(b) (i) simply writing monomers form / react to form polymers gains no mark
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monomers join / bond / combine / link to form polymers = 1 mark the mark is for the idea of joining to gain the second mark the idea of the relative size of monomer and polymer is required small molecules join to form a polymer (2 marks) many monomers join to form a polymer (2 marks) monomers join to form a large molecule / long chain (2 marks) many molecules join together (2 marks)
for 1 mark each 2
(ii) polyethene / poly(ethene) / polythene
don’t worry too much about the exact positioning of the C6H5 at the end of the bond
placement of linking bonds inside / outside brackets is not important must have n
for 1 mark each [8]
M6. (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
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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
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
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• country has oil refineries / cracking plants
• very pure product
• faster process 4
[10]
Page 37
C1.6 Answers
M1. (a) (i) pressing 1
(ii) dissolve 1
(b) bromine 1
(c) temperature needs to be high / above 100 °C
allow melting point 1
or (sunflower oil has a) high(er) boiling point
or boiling point of water is not high enough
any one from:
• remove water / make potato crisp(er)
accept water makes potato soft / soggy
• adds / gives flavour 1
[5]
M2. (a) D 1
C 1
A 1
letters must be in the order shown
(b) (i) floats 1
(ii) an emulsion 1
[5]
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M3. (i) unsaturated 1
(ii) hydrogen 1
higher 1
[3]
M4. (i) (poly)unsaturated
accept monounsaturated 1
(ii) (turns) colourless or colour disappears / decolourises
do not accept clear 1
stays the same colour / orange / no change
allow yellow-orange / orange-brown / red-orange 1
(iii) (react) with hydrogen / H2 / hydrogenation 1
any one from:
• heated / 60 °C
• catalyst / nickel 1
[5]
M5. (a) (i) water and oil do not mix / are immiscible
ignore density 1
or
don’t dissolve each other
ignore emulsifier alone 1
(ii) any two from:
• emulsifier
• forms an emulsion
accept description of an emulsion
• holds the two components together
accept stops them separating / they mix
allow bonds / binds for holds
• by lowering the surface tension
accept a description of how an emulsifier works for two marks eg ‘tadpole’ diagram or dispersal of oil drops
2
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(b) (i) (because they contain) a double (carbon carbon) bond
accept unsaturated
ignore poly or mono 1
(ii) results suggest sunflower oil is best
or
‘the one that took the least time’ 1
because (sunflower oil) has the highest amount of unsaturation / most double bonds / least saturated
ignore uses up I2 most quickly
second mark is dependent on first 1
(c) (i) any one from:
• have a higher melting point than (vegetable) oil
• are solid at (room temperature) / hardened / harder
accept useful as spreads or doesn’t soak into bread
ignore hard / soft(er) 1
(ii) any two from:
• hydrogen added
do not accept ‘water’
• to carbon carbon double bond / to saturate
• (nickel) catalyst / temperature 60 – 150 °C
wrong catalyst doesn’t get this mark
ignore high / warm temperature 2
[9]
M6. (a) (i) (healthiest oil is) sunflower (oil) or rapeseed (oil)
sunflower (oil) is healthiest because it has less saturated fat than both olive (oil) and corn (oil)
or
rapeseed (oil) is healthiest because it has the lowest value of saturated fat compared with the other oils
1
sunflower (oil) is healthiest because it has the highest value of polyunsaturated fat compared with all the other oils
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or
rapeseed (oil) is healthiest because it has more polyunsaturated fat than both olive (oil) and corn (oil)
1
no mark for the choice of oil
accept the use of values from the table for these comparisons
(ii) no, because hydrogen adds to the unsaturated fat or no, because hydrogen reduces the number of carbon–carbon double bonds
accept no because reacting with hydrogen increases number of single bonds
1
therefore there will be less polyunsaturated fat
accept therefore there will be more saturated fat 1
(b) molecules in egg yolk act as emulsifiers
accept lecithin molecules act as emulsifiers 1
because molecules in egg yolk have a ‘head’ which dissolves in / attracted to water
accept because molecules in egg yolk are hydrophilic 1
because molecules in egg yolk have a ‘tail’ which dissolves in / attracted to oil
accept because molecules in egg yolk are hydrophobic 1
[7]
M7. (i) 23 to 59
accept 36 1
(ii) decolourise or (orange to) colourless
ignore discolours / fades
do not allow oil decolourises 1
(because bromine reacts with the) (carbon) double bond
ignore alkenes or reference to unsaturation 1
(iii) any one from:
• an anomalous result (11.2) / Test 2
accept (= 23.6)
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• 11.2 / Test 2 is ignored when averaging
accept average of tests 1 and 3 1
(iv) unsaturation 67%
average was less than it should be / only 26.8 cm3
1
(this means there is) 33% saturated fat
it should have been 28.0 cm3 to give a percentage of 70% 1
[6]
Page 42
C1.7 Answers
M1. (a) Layer A = crust / tectonic plates / (not named type of rock) Layer B = mantle / magma
each for 1 mark 2
(b) Layer C is liquid / molten (accept mostly liquid) but layer D is solid Layer D is more dense than layer C. / accept they have different densities Layer D is hotter than layer C. / accept they have different temperatures (Do not accept hardness / viscosity)
any one for 1 mark 1
[3]
M2. (a) (i) old animals / fossils / rocks match (when the continents are put together)
or (continents) fit together
ignore ‘they are the same shape’ 1
(ii) any two from:
• continents / plates cannot move (thousands of kilometres)
accept the continents / plates are attached to the Earth or continents / plates cannot drift / float
• modern / new animals are different
• a land bridge (could explain the matching fossils / rocks)
ignore ‘no evidence’ ‘no proof’ ‘no reputation’ 2
(b) crust
allow lithosphere 1
mantle 1
year 1
[6]
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M3. (a) (i) X – mantle 1
Y – inner core
do not accept solid core 1
(ii) different to the crust or contains a lot of (heavy) metals
accept iron and nickel for metals 1
higher (average) density or denser
density higher than 5500 (kg/m3) gets 2 marks 1
(b) animals were able to move from one continent to the other 1
(when bridge broke) animals evolved differently accept animals adapted differently
1
(c) (i) earthquakes occur at the boundary between plates or earthquakes occur where plates push against each other
1
there are no plate boundaries running through Britain 1
(ii) convection currents (in the mantle) or heat released by (natural) radioactive processes
accept Britain is not near the edge of a plate 1
[9]
M4. (a) (i) convection (currents)
accept (currents) which move the plates 1
(ii) less dense (molten) rock / magma rises / moves up
or more dense (molten) rock / magma falls / moves down 1
heat (is transferred / conducted) to the mantle / crust
(resulting from natural) radioactive processes (in the core) 1
or radioactivity
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accept radiation provided there is no
contradiction as in, for example, radiation from the Sun
or fission
do not credit fusion 1
(b) any two from
(formation of fold) mountains
or deformation(s)
hot springs
do not credit just springs
(oceanic) ridges
(oceanic) trench(es)
rift(s)
seismic waves
subduction
or recycling of rocks
tsunami(s)
do not credit tidal waves
volcano(es)
or volcanic activity / sill(s) dyke(s) lava flow(s) 2
[6]
M5. (a) (i) nitrogen / N2
1
(ii) carbon dioxide / CO2
1
(b) (i) humans / scientists had not evolved
accept it was billions / millions of years ago
allow too long ago 1
(ii) temperature is above 100°C or any water would evaporate / boil
accept Venus is too hot 1
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(c) any three from:
• used by plants
• used for photosynthesis
accept plants take in carbon dioxide and give out oxygen for the first two bullet points ie 2 marks
• dissolves in oceans / seas
allow absorbs into oceans / seas
• used to form the shells / skeletons of marine organisms
• locked up as limestone / carbonates
• locked up as fossil fuels / oil / coal 3
[7]
M6. (a) (i) water vapour given out from volcano
accept steam not hydrogen and oxygen combining to form water
1
condensed
accept rain / clouds formed just ‘cools’ is insufficient 1
(b) nitrogen (left) N
do not accept N 1
oxygen (right) O
do not accept O 1
[4]
M7. (a) (i) burning / breathing / respiration / fuels / food
for 1 mark each 2
(ii) 1. rock is heated / subducted (owtte) / close to magma / melted 1. rock is decomposed / carbon dioxide released through volcanoes
for 1 mark each 2
(b) carbon dioxide reacts / dissolves in sea-water / dissolves in rain water insoluble carbonates / calcium carbonate are / is formed carbon dioxide turned into shells / coral / limestone / chalk / sediments also soluble hydrogencarbonates (calcium / magnesium) are formed photosynthesis by plants
any three for 1 mark each 3
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(c) (i) sea unable to absorb all the extra carbon dioxide being produced more trees being cut down / deforestation increased burning of fuels / more cars / more industry (not more people)
any one for 1 mark 1
(ii) global warming / greenhouse effect or effects such as melting ice caps / rising sea levels / climatic change / more deserts (not changes to ozone layer)
for one mark 1
[9]
M8. (a) to remove solid / dust particles 1
(b) because at –200 °C both (water and carbon dioxide) are solids 1
this would therefore block pipes / equipment 1
(c) oxygen 1
(d) (i) helium 1
(ii) nitrogen > argon > oxygen 1
[6]
