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.
(3)
(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
(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 CH4.
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)
Q3.
Choose words from this list to complete the sentences,
ammonia
nitrogen
electrical
carbon dioxide
heat
hydrogen
solar
sound
(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)
Q4.
Read the passage, which is from the start of a magazine article. It will
help you to answer the questions.
Third rock from the Sun
Geologists now have evidence that the Earth’s crust began to form about four
and a half billion years ago. The surface of the Earth was then at
temperatures well above 100 °C and the atmosphere was mostly carbon
dioxide with some ammonia, methane and water vapour. About a quarter of a
billion years after it had first formed, the crust had become thicker and had
cooled down to below 100 °C.
Slowly, over a period of about three billion years, oxygen became established
in the atmosphere. Some was released from the Earth’s interior by volcanoes
and some was produced, by the process of photosynthesis, by algae which
had evolved in the seas.
(a)
Explain how the first seas formed.
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
(2)
(b)
Briefly describe two processes which reduced the proportion of
carbon dioxide in the Earth's atmosphere over the period of three
billion years.
1.
..................................................................................................
...............................
............................................................................................................
.........................
2.
..................................................................................................
...............................
............................................................................................................
.........................
(2)
(Total 4 marks)
Q5.
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)
Q6.
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)
(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)
Q7.
(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
hydrogencarbonates
hydrocarbons
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.
NAME OF FRACTION
NUMBER OF CARBON
ATOMS IN MOLECULES
petroleum gases
1 to 4
gasoline
4 to 12
naphtha
7 to 14
kerosene
11 to 15
diesel oil
14 to 19
lubricating oil
18 to 30
residue
more than 30
Naphtha burns more easily than diesel oil.
Explain why.
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
(1)
(Total 2 marks)
Q8.
The diagram represents an atom. Choose words from the list to label
the diagram.
electron
ion
neutron
nucleus
(Total 3 marks)
Q9.
Crude oil is a mixture of many compounds. The diagram below
shows some of the processes that take place in a petrochemical plant.
(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:
Draw the structure of a molecule of propane in the space below.
(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)
Q10.
The high demand for petrol (octane) can be met by breaking down
longer hydrocarbons, such as decane, by a process known as cracking.
(a)
Apart from heat, what is used to make the rate of this reaction
faster?
............................................................................................................
........................
(1)
(b)
Octane is a hydrocarbon.
(i)
What does hydrocarbon mean?
..................................................................................................
........................
..................................................................................................
........................
(1)
(ii)
Give the molecular formula of octane.
..................................................................................................
........................
(1)
(c)
The hydrocarbon X is used to make poly(ethene).
(i)
What is the name of X?
..................................................................................................
........................
(1)
(ii)
What is the name of the process in which X is changed into
poly(ethene)?
..................................................................................................
........................
(1)
(Total 5 marks)
Q11.
Fractional distillation is used to separate fractions in the crude oil
mixture.
(a)
Draw a line to join each fraction to its use as a fuel. One line has
been drawn for you.
(2)
(b)
(i)
Why does petrol separate from the other fractions in the
crude oil mixture?
..................................................................................................
........................
..................................................................................................
........................
(1)
(ii)
Petrol contains the elements carbon and hydrogen only.
Which two of the substances in the diagram are formed when
petrol burns?
1
.........................................................................................
..........................
2
.........................................................................................
.........................
(2)
(Total 5 marks)
Q12.
The uses of elements depend on their properties.
(a)
Carbon and iron are both elements. What is an element?
............................................................................................................
....................
............................................................................................................
....................
(1)
(b)
Complete the sentences by crossing out the words that are wrong.
The first one has been done for you.
(2)
(c)
In the box are the names of three metals.
copper
iron
sodium
Which one of these is not a good metal for making the cooking
pot? Give a reason for your answer.
Metal
..................................................................................................
....................
Reason
..................................................................................................
..................
............................................................................................................
....................
............................................................................................................
....................
(2)
(Total 5 marks)
Q13.
Magnesium chloride is a useful salt.
The flow diagram shows how it can be made.
(i)
Describe how calcium hydroxide can be made from limestone.
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
(2)
(ii)
Write a word equation for the neutralisation of magnesium
hydroxide with a suitable acid to form magnesium chloride.
............................................................................................................
.........................
(2)
(Total 4 marks)
Q14.
Transition elements and their compounds have many uses.
Iron oxide and cobalt oxide have been added to the glazes on pottery for
hundreds of years.
(a)
State why transition metal oxides are added to pottery glazes.
............................................................................................................
.........................
(1)
(b)
Use the table of ions on the Data Sheet to help you work out the
formula of iron(III) oxide.
............................................................................................................
.........................
(1)
(c)
Cobalt oxide is reacted with hydrogen to form cobalt.
(i)
Balance the equation for this reaction.
(1)
(ii)
Cobalt is mixed with other transition metals to make alloys.
These alloys are used to make cutting tools which remain
sharp at very high temperatures. They can cut through other
metals.
Suggest two properties of transition metals that make them
suitable for making cutting tools.
1
.........................................................................................
...............................
..................................................................................................
.........................
2
.........................................................................................
...............................
..................................................................................................
.........................
(2)
(Total 5 marks)
Q15.
The table gives some data about four fuels, A, B, C and D.
Cost in
pence
per
Energy
in kJ per
Energy
per penny
in
100 g
100 g
kJ
A
6.0
4 800
800
B
4.0
1 200
300
C
3.5
2 800
800
D
18.0
14 400
800
Fuel
Gas ( ) formed on burning
Carbon
dioxide
Sulphur
dioxide
Water
vapour
A student was asked to use the data in the table to compare these four
fuels, and then place the fuels in an order.
The order that the student chose was:
Use the information in the table to suggest reasons why the student
chose this order.
To gain full marks in this question you should write down your ideas in
good English. Put them into a sensible order and use the correct
scientific words.
.....................................................................................................................
..........................
.....................................................................................................................
..........................
.....................................................................................................................
..........................
.....................................................................................................................
..........................
.....................................................................................................................
..........................
.....................................................................................................................
..........................
.....................................................................................................................
..........................
.....................................................................................................................
..........................
.....................................................................................................................
..........................
(Total 4 marks)
Q16.
Bags of readi-to-mix concrete contain three ingredients.
Readi-to-mix Concrete
contains
cement
crushed rock
sand
Complete each sentence by choosing the correct words from the box.
clay
water
limestone
salt
slaked lime
Cement is made by heating.......................................... and
......................................... in a rotary kiln.
To make concrete, the contents of the bag of readi-to-mix concrete must
be mixed with
............................................................................... .
(Total 3 marks)
Q17.
(a)
Complete this sentence about crude oil.
Crude oil is mainly a mixture of compounds called
...................................... which
contain carbon and hydrogen only.
(1)
(b)
The diagram shows a laboratory experiment used to separate
crude oil.
Complete each sentence by choosing the correct words from the
box.
condensation
distillation
melting
evaporation
sublimation
The main process taking place at A is
.......................................................................
The main process taking place at B is
.......................................................................
This method of separating crude oil is called
............................................................
(3)
(c)
Complete this sentence by crossing out the word in each box that is
wrong. The first one has been done for you.
This method of separating crude oil works because the
the molecules are,
the
they are.
their boiling point and the
volatile
(1)
(Total 5 marks)
Q18.
Known crude oil reserves are being used up rapidly. Crude oil is
used to produce many useful fuels, such as petrol. One way to conserve
crude oil reserves would be to increase the production of bio-fuels.
(a)
Ethanol can be produced for use as a bio-fuel. Cars can be
powered by ethanol or ethanol–petrol mixtures.
Sugar cane can be fermented to give a mixture of water (boiling
point 100 °C) and ethanol (boiling point 78 °C).
(i)
How can ethanol be separated from water?
..................................................................................................
........................
..................................................................................................
........................
(1)
(ii)
Ethanol, C2H5OH, burns to release heat energy.
Complete the balanced symbol equation by writing in the
formulae of the two products.
C2H5OH
+
3O2
2.........
+
3.........
(2)
(b)
The cost of producing a bio-fuel, such as ethanol, by fermentation,
is at least three times higher than the production cost of petrol. It
costs less to produce ethanol from alkanes. In the production, the
vapour of an alkane is passed over a hot catalyst.
Ethene is then converted into ethanol.
(i)
What has happened to the hexane to produce ethene?
..................................................................................................
........................
(1)
(ii)
Complete the structural formula for ethene, C2H4.
C
C
(1)
(iii)
Name the compound that is added to ethene to produce
ethanol, C2H5OH.
..................................................................................................
........................
(1)
(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.
............................................................................................................
........................
............................................................................................................
........................
............................................................................................................
........................
............................................................................................................
........................
............................................................................................................
........................
............................................................................................................
........................
............................................................................................................
........................
............................................................................................................
........................
(4)
(Total 10 marks)
Q19.
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
3g
Fat
27 g
of which saturates
unsaturates
9g
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)
(Total 5 marks)
Q20.
Many everyday items are made from iron.
(a)
Haematite is an ore of iron. Haematite contains iron oxide, Fe2O3.
(i)
What is the meaning of the term ore?
..................................................................................................
.........................
..................................................................................................
.........................
(1)
(ii)
Iron can be produced by reacting iron oxide with carbon in a
blast furnace.
What type of reaction produces the iron?
..................................................................................................
.........................
..................................................................................................
.........................
(1)
(iii)
The word equation for this reaction is:
iron oxide
+
dioxide
carbon
→
iron
+
carbon
Complete and balance the symbol equation for this reaction.
.....Fe2O3
+
...................
.....C
→
................... +
(2)
(b)
Pure iron is relatively soft and not very strong.
The iron from the blast furnace is very hard and brittle. It contains
about 4% carbon and is used as cast iron.
Explain the differences in the properties of pure iron and cast iron
by referring to the diagrams.
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
(3)
(c)
The diagram shows the way in which iron is extracted, used and
recycled.
Explain why the recycling of iron is necessary for sustainable
development.
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
(3)
(Total 10 marks)
Q21.
Life on Earth would not exist without the atmosphere. Billions of
years ago the composition of the Earth’s atmosphere was very different
from the composition today.
(a)
Label the pie chart below to show the percentages and names of
the two main gases in the Earth’s atmosphere today.
(2)
(b)
There is evidence that the composition of the Earth’s atmosphere is
still changing. One possible reason is that many power stations
generate electricity by burning fossil fuels such as coal, oil or
natural gas. Sulfur dioxide, SO2, is produced when coal burns in air.
(i)
What environmental problem does sulfur dioxide cause?
..................................................................................................
.........................
..................................................................................................
.........................
(1)
(ii)
How could this environmental problem be reduced in coalfired power stations?
..................................................................................................
.........................
..................................................................................................
.........................
(1)
(iii)
Gas-fired power stations burn methane, CH4, in air.
Complete the word equation for this reaction.
methane + ............................... → carbon dioxide 
...............................
(2)
(c)
Excess carbon dioxide should be prevented from entering the
atmosphere.
Explain why.
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
(2)
(d)
Carbon dioxide is produced when fossil fuels burn in power
stations. The diagram represents one idea to prevent excess
carbon dioxide from entering the atmosphere.
Use the diagram to explain how carbon dioxide can be prevented
from entering the atmosphere.
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
(2)
(Total 10 marks)
Q22.
(a) Two hundred years ago, scientists thought that the Earth was
about 400 million years old. This estimate came from the idea that
the centre of the Earth was still molten. More recently,
measurement of radioactivity in rocks has shown that the Earth is
much older than 400 million years.
Suggest one reason why scientists now know that the Earth is
much older than 400 million years.
............................................................................................................
.........................
............................................................................................................
.........................
(1)
(b)
About one hundred years ago there was a scientist called Alfred
Wegener. He found evidence that the continents, such as South
America and Africa, had once been joined and then drifted apart.
Use the diagram to suggest two pieces of evidence that could be
used to show that the continents had once been joined.
1
..................................................................................................
................................
............................................................................................................
.........................
2
..................................................................................................
................................
............................................................................................................
.........................
(2)
(c)
About fifty years ago, new evidence convinced scientists that the
Earth’s crust is made up of tectonic plates that are moving very
slowly.
Give two pieces of evidence that have helped to convince these
scientists that the tectonic plates are moving.
1
..................................................................................................
................................
............................................................................................................
.........................
2
..................................................................................................
................................
............................................................................................................
.........................
(2)
(Total 5 marks)
Q23.
Polymers are used to make many materials that people need.
(a)
Plastic bags are used to carry, protect and store food. Plastic bags
are made from polymers.
(i)
Ethene is the small molecule (the monomer) used to make
the polymer for this plastic bag.
Name the polymer that is made from ethene.
..................................................................................................
.........................
(1)
(ii)
Use the correct word from the box to complete the sentence
about ethene.
condensing
corroding
cracking
Ethene is made by breaking down large hydrocarbon
molecules into smaller
hydrocarbon molecules by a process called
.....................................................
(1)
(iii)
The hydrocarbon ethene has the formula C2H4
Complete the sentence about ethene.
Ethene is a hydrocarbon made up of carbon and
.......................................... atoms.
(1)
(b)
The hydrocarbons used to make ethene come from crude oil. The
properties of hydrocarbons are linked to the number of carbon
atoms in their molecules.
Number of carbon atoms
5
6
7
8
9
Boiling point in °C
36
69
99
125
151
(i)
Use the data in the table to complete the bar chart.
(2)
(ii)
What happens to the boiling point of a hydrocarbon as the
number of carbon atoms increases?
..................................................................................................
.........................
(1)
(iii)
All the hydrocarbons in the table are found in petrol. Petrol is
one of the fractions separated from crude oil.
Describe how the fractions are separated from crude oil.
..................................................................................................
.........................
..................................................................................................
.........................
..................................................................................................
.........................
..................................................................................................
.........................
..................................................................................................
.........................
(2)
(c)
Most plastic bags that are made of hydrocarbons are not
biodegradable.
Used plastic bags can be:
•
dumped into large holes, which is called landfill
•
burned to give out heat energy, which would produce large
amounts of gases.
Would burning used plastic bags be better for the environment than
dumping them in landfill?
Explain your answer.
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
(2)
(Total 10 marks)
Q24.
Limestone contains calcium carbonate.
(a)
Calcium carbonate has the formula CaCO3.
Complete the sentence by writing in the correct numbers.
The formula of calcium carbonate is made up of 1 calcium atom,
............ carbon atom(s)
and ............ oxygen atom(s).
(2)
(b)
When limestone is heated it forms two other compounds.
(i)
State one safety precaution that you should take when
heating limestone.
..................................................................................................
.........................
(1)
(ii)
Name the white solid produced.
..................................................................................................
.........................
(1)
(iii)
Why does a piece of limestone lose mass as it is heated?
..................................................................................................
.........................
..................................................................................................
.........................
(1)
(d)
A company wants to quarry limestone. There are some houses
near the quarry.
Residents in the houses say that they do not want a quarry next to
them.
(i)
Suggest two reasons why they do not want the quarry next to
them.
1
.........................................................................................
...............................
..................................................................................................
.........................
2
.........................................................................................
...............................
..................................................................................................
.........................
(2)
(ii)
Suggest one possible benefit to the residents of having a
quarry near their houses.
..................................................................................................
.........................
..................................................................................................
.........................
(1)
(Total 8 marks)
Q25.
When electricity passes through a thin wire, the wire gets hot. If the
wire gets very hot, it may glow. This idea is used in filament lamps.
(a)
The table shows some metals and their melting points.
Metal
Melting point in °C
Aluminium
660
Copper
1084
Iron
1540
Tungsten
3410
Which metal in the table should be used to make the wire in a
filament lamp?
Give a reason for your answer.
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
(2)
(b)
The table shows some gases.
Gas
Argon
Carbon dioxide
Oxygen
Sulfur dioxide
Which gas in the table should be used in a filament lamp?
Give a reason for your answer.
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
............................................................................................................
.........................
(2)
(Total 4 marks)
Q26.
A vegetable oil can be extracted from olives.
(a)
The diagram shows the first step in this extraction.
Use the correct word from the box to complete the sentence about
this first step.
evaporating
filtering
pressing
The olive oil is extracted by
................................................................... the olives.
(1)
(b)
The contents from the mortar are tipped into a beaker. The mixture
is left to settle.
(i)
What is the name of the colourless liquid?
..................................................................................................
.........................
(1)
(ii)
How can the olive seeds and skins be removed from the
liquids?
..................................................................................................
.........................
..................................................................................................
.........................
(1)
(Total 3 marks)
Q27.
Lithium metal is used in alkaline batteries.
(a)
The diagram shows the atoms in lithium metal.
Why is lithium metal described as an element?
............................................................................................................
.........................
............................................................................................................
.........................
(1)
(b)
The diagram below represents a lithium atom.
Choose words from the box to label parts of the atom.
bond
electron
molecule
nucleus
(2)
(Total 3 marks)
Q28.
Scientists study the atmosphere on planets and moons in the Solar
System to understand how the Earth’s atmosphere has changed.
(a)
Millions of years ago the Earth’s atmosphere was probably just like
that of Mars today.
The table shows data about the atmospheres of Mars and Earth as
they are now.
Mars
Earth
nitrogen
3%
nitrogen
78%
oxygen
trace
oxygen
21%
water
trace
water
trace
carbon dioxide
95%
carbon dioxide
trace
Average surface temperature –23 °C
Average surface temperature 15 °C
Suggest what has caused the main gases in the Earth’s
atmosphere of millions of years ago to change to the present-day
atmosphere.
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(2)
(b)
Titan is the largest moon of the planet Saturn. It has an atmosphere
that, like the Earth’s, contains mainly nitrogen. Methane is the other
main gas.
Main gases in
Titan’s atmosphere
Percentage (%)
Boiling point in °C
Nitrogen
95
–196
Methane
5
–164
Average surface temperature –178 °C
When it rains on Titan, it rains methane! Explain why.
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........................
(2)
(c)
Ultraviolet radiation from the Sun produces simple alkenes, such as
ethene and propene, from methane in Titan’s atmosphere.
(i)
Draw the structure of propene, C3H6, to show the covalent
bonds.
(1)
(ii)
Explain how propene molecules form a polymer. You should
name the polymer formed.
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(3)
(Total 8 marks)
Q29.
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.
Explain why.
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(4)
(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.
Suggest why.
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(3)
(Total 7 marks)
Q30.
A company compared the relative ‘unsaturation’ of five oils. Bromine
water was added from a burette to equal amounts of each oil until the
bromine water remained orange-yellow.
The volume added was recorded.
Type of oil
Volume of bromine water
added in cm3
Maize
25.6
Olive
6.1
Palm
4.9
Soya Bean
29.9
Sunflower
25.1
(i)
What would you see when the first few drops of bromine water are
added to
each oil?
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.......................
(1)
(ii)
What do these results tell you about sunflower oil compared with
the other oils?
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(2)
(Total 3 marks)
Q31.
Titanium is used in aircraft, ships and hip replacement joints.
Titanium is as strong as steel but 45% lighter, and is more resistant to
acids and alkalis.
Most titanium is produced from its ore, rutile (titanium oxide), by a batch
process that takes up to 17 days.
Titanium reactors produce about 1 tonne of the metal per day.
Iron blast furnaces produce about 20 000 tonnes of the metal per hour.
(a)
Give one property of titanium that makes it more useful than steel
for hip replacement joints.
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........................
(1)
(b)
In the reactor magnesium is used to produce titanium. If carbon
were used instead of magnesium, no titanium would be produced.
What does this tell you about the relative reactivities of carbon,
magnesium and
titanium?
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(2)
(c)
The use of titanium is limited because it is expensive.
Explain why titanium costs more than steel.
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(3)
(Total 6 marks)
Q32.
The hydrocarbons in crude oil can be separated into useful
fractions.
Fraction
Boiling
point
in °C
Carbon
chain
length
Relative %
in crude
oil
Relative %
demand
Naphtha
20–180
5–9
10
20
Gasoline (petrol)
20–200
5–10
10
20
Kerosene
(paraffin)
180–260
10–16
15
23
Diesel
260–340
14–20
20
25
Fuel oil
370–600
20–70
45
12
(a)
Why does gasoline (petrol) have a lower boiling point than fuel oil?
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(1)
(b)
Suggest why gasoline (petrol) costs more than fuel oil.
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(2)
(c)
Describe how fuel oil can be changed into gasoline (petrol).
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(2)
(Total 5 marks)
Q33.
Metals and their alloys have many uses.
(a)
Dentists use a smart alloy to make braces that gently push teeth
into the right position.
What is meant by a smart alloy?
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(1)
(b)
Pure copper is made up of layers of copper atoms. Brass is an alloy
of copper and zinc.
Why are the physical properties of brass different from the physical
properties of pure copper?
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(2)
(c)
Nearly all zinc is obtained from ores that also contain lead. The
metals zinc and lead can be extracted by reducing their oxides
using carbon.
(i)
Choose one element from the box below to complete the
sentence about the reduction of zinc oxide.
lead
nitrogen
oxygen
Zinc oxide is reduced by carbon, which takes
away..................................................
to leave zinc metal.
(1)
(ii)
The melting points and boiling points of lead and zinc are
given in the table.
Metal
Lead
Zinc
Melting point in °C
328
420
Boiling point in °C
1740
907
The furnace operates at a temperature of 1200 °C.
Suggest how the lead metal and zinc metal are separated in
the furnace.
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(2)
(Total 6 marks)
Q34.
Tablet containers are often made from two different polymers.
(a)
Ethene, C2H4, and propene, C3H6, can be made from crude oil.
(i)
Complete the following sentence.
Ethene and propene are called hydrocarbons because they
are made up of carbon
and ..................................................... atoms only.
(1)
(ii)
Ethene molecules are used to form poly(ethene) molecules.
Complete the diagram to show the poly(ethene) molecule.
Ethene molecules
Poly(ethene) molecule
(2)
(b)
The tablet containers could be disposed of in a landfill site or could
be recycled.
(i)
Suggest two reasons why disposing of the tablet containers
in a landfill site could cause problems.
1
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2
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(2)
(ii)
Suggest one reason why recycling the tablet containers would
be difficult.
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(1)
(Total 6 marks)
Q35.
The label on a bottle of salad dressing shows that the dressing
contains the following ingredients.
Ingredients
Water
Vegetable oil
Egg yolk
Sugar
Flour
Vinegar
Salt
(a)
Extract of spices
Preservative E202
Emulsifier E405
One of the main ingredients in salad dressing is vegetable oil.
(i)
Use the correct word from the box to complete the sentence
about the extraction of vegetable oil.
crushed
evaporated
hardened
To extract the vegetable oil, the fruits or seeds of plants are
first
......................................................... .
(1)
(ii)
The liquids can be separated from the solid parts of the fruits
or seeds by filtering.
Suggest one reason why separation by filtering is better than
separation by distilling.
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(1)
(b)
(i)
A mixture of vegetable oil and water is shaken and left to
stand for several minutes. The diagram shows the result.
Complete the following sentence.
The vegetable oil and water
.................................................................................... .
(1)
(ii)
A mixture of vegetable oil, water and egg yolk is shaken and
left to stand for several minutes.
The diagram shows the result.
Use words from the box to complete the sentence.
additive
distil
emulsion
extract
mix
separate
The egg yolk causes vegetable oil and water to
........................................................
and form an ..................................................... .
(2)
(Total 5 marks)
Q36.
A headline from 27 December 2004 read:
(a)
Use words from the box to complete the sentences about
earthquakes.
convection
radioactive
tectonic
volcanic
The earthquake was caused by the movement of two of the Earth’s
......................................................... plates.
The energy for this movement comes from the heat released by
natural
......................................................... processes.
(2)
(b)
It was estimated that 300 000 people died as a result of the tsunami
in 2004.
Some newspapers criticised scientists for not predicting the
tsunami, because if people had been warned they could have
moved to safety.
(i)
Suggest why we can only estimate that 300 000 people died
as a result of the tsunami.
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(2)
(ii)
Explain why scientists could not have predicted the tsunami.
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(2)
(Total 6 marks)
Q37.
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?
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(1)
(ii)
In the sentence below, draw a ring around the correct answer.
The type of environmental pollution caused by
global dimming
smoke particle
is
global warming
rising sea
levels
(1)
(iii)
Suggest how the burning of fossil fuels may cause climate
change.
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(2)
(b)
The table shows the percentage of electricity generated by different
energy sources.
Energy
sources
Percentage
(%)
Renewables
Nuclear
Coal
Gas and Oil
8
20
32
40
Complete the bar chart to show the percentage of electricity
generated by coal and by gas and oil.
(2)
(Total 6 marks)
Q38.
Hydrogen is an element.
(a)
The diagram shows the parts of a hydrogen atom.
Use words from the box to label the diagram.
electron
group
nucleus
symbol
(2)
(b)
Hydrogen can be used as a clean fuel for cars.
(i)
When hydrogen burns in air, it reacts with another element.
Complete the word equation for this reaction.
hydrogen
+ .................................
→
water
(1)
(ii)
Suggest one reason why hydrogen is called a clean fuel.
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(1)
(Total 4 marks)
Q39.
Crude oil is the source of many useful materials. Crude oil is
separated into fractions by fractional distillation.
(a)
Describe how the naphtha fraction separates from the other
fractions.
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(2)
(b)
The naphtha fraction is often used to make other useful materials.
This involves the cracking of hydrocarbons in the naphtha fraction.
For example:
decane
C10H22
(i)
→
→
hexane
C6H14
+
+
ethene
C2H4
Balance the symbol equation given above.
(1)
(ii)
Describe how cracking is carried out.
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(2)
(iii)
Why does ethene have different chemical properties from
decane and hexane?
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(2)
(c)
Ethene is used as the starting material for many polymers. The
most common polymer is poly(ethene). One hydrocarbon molecule
in poly(ethene) will contain thousands of carbon atoms.
Complete the diagram to show the bonds in ethene.
H
H
C
C
H
H
(1)
(d)
Read the following information.
Landfill, Incineration, Recycling and Re-use of Poly(ethene)
People could be encouraged to re-use their poly(ethene) bags and
containers.
Recycling poly(ethene) saves raw materials and energy needed to make new
plastic. When polymers are recycled the plastics must be collected,
transported, sorted into different types by hand and washed. This requires
the use of fossil fuels and is expensive.
Poly(ethene) can be burnt in an incinerator with other household waste. The
heat released could be used to make steam to drive an electric generator.
Surplus heat could be used to heat greenhouses used for growing
vegetables. Incineration at too low a temperature can produce harmful
substances. The residue (ash) has to go to landfill.
Landfill is probably the easiest way to dispose of polymers and it is cheap.
Polymers are often mixed in with other household rubbish. Household waste
does not get sorted into different materials because it is disposed of in the
same hole in the ground. When the hole is eventually full, the waste is
covered by a layer of soil to stop it smelling. The waste gets compressed
under its own weight. Most polymers, such as poly(ethene), are not
biodegradable so will remain in the ground forever.
You are asked to decide which option for the disposal of
poly(ethene) will be put forward in your area. You decide that
recycling is the best option.
Suggest one economic argument and one environmental
argument that will be made against recycling.
For each argument made, how will you persuade those making the
argument to accept your option?
(You must use only one sentence for each argument made against
your decision and only one sentence for your response to it.)
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(4)
(Total 12 marks)
Mark Scheme
M1.
(a)
each bar correct height (2 bars) to less than
1 mark for each
½ square
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
(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]
M2.
(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)
C2H6
C5H12
each for 1 mark
[NB figures must be subscripted]
2
[7]
M3.
(a)
(b)
nitrogen / N2
[Do not allow N or N2] for 1 mark
heat
for 1 mark
(c)
carbon dioxide / CO2
for 1 mark
[3]
##
(a)
either any two points (1) each from
* (surface) below 100 °C (the surface) below the boiling point
of water
* (allowed the) condensation (of water vapour)
accept (rate of) condensation greater than
(the rate of) evaporation
* from the atmosphere
accept from the air
or condensed water (vapour) (1)
was pulled by gravity into depressions (1)
or idea of impervious sea bed
or from comets (which crashed on the Earth) (1)
ice (from these) melted (1)
2
(b)
any two processes (1) each from
* dissolving in (sea) water
* (taken in during) photosynthesis
accept taken in by algae or plants
•
formation of carbonate(s)
or calcium carbonate or chalk or
calcite
accept formation of shells or bones or
corals
2
[4]
M5.
(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]
M6.
(a)
(i)
do not credit CH3CH3
1
(ii)
do not credit C2H4
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]
M7.
(a)
hydrocarbons
for 1 mark
1
(b)
less carbon atoms / smaller molecule
for 1 mark
1
[2]
M8.
electron
nucleus
neutron
each for 1 mark
[3]
##
(a)
(i)
(fractional) distillation/fractionation
for 1 mark
1
(b)
(i)
cracking/decomposition
for 1 mark
1
(iii)
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
(e)
(n must be on (right))
= 2 marks
= 2 marks
= 1 mark
= 1 mark
(Double bond loses both marks)
= 0 marks
OR
= 2 marks
= 1 mark
= 2 marks
= 1 mark
= 1 mark
2
[7]
M10.
(a)
catalyst
1
(b)
(i)
made up of only carbon and hydrogen
1
(ii)
C8H18
1
(c)
(i)
ethene
1
(ii)
polymerisation
1
[5]
M11.
(a) all three lines correct two marks
one or two lines correct one mark
two ticks only
accept diesel oil joined to cars
1
(b)
(i)
because it has a different boiling point
accept because of its boiling point
or it has a boiling point of 40 °C
1
(ii)
CO2 or carbon dioxide
1
H2O or water
accept steam
1
[5]
M12.
(a)
made of atoms which contain the same number of protons
accept made of only one type of atom
accept cannot be broken down into anything
simpler by chemical means
1
(b)
non-metals
1
metals
1
(c)
sodium
1
too reactive (with water or air)
accept has a low melting point or
will melt or not strong or will explode or will
burn
do not accept dangerous (neutral)
do not accept iron as rusting or
copper or sodium as expensive (neutral)
do not accept not a good conductor of heat
1
[5]
M13.
(a)
(i)
heat (the limestone)
accept decompose limestone
accept heat with coke
1
add water / slake
dependent on 1st mark unless they say add
water to the calcium oxide
1
(ii)
magnesium hydroxide +
hydrochloric acid
1
→ magnesium chloride + water / H2O
1 mark for each side of the equation
(if a symbol equation is given then give 1
mark for correct formulae (all) and 1 mark
for balancing)
1
[4]
M14.
(a)
colour
1
(b)
Fe2O3 or (Fe3+)2 (O2-)3
2 and 3 should be below halfway on Fe and
O
1
(c)
(i)
4 4
or correct multiples
1
(ii)
any two from:
ignore references to malleable / ductile /
conductivity / stiff / boiling point / density
•
high melting point
accept can withstand high temperatures
•
strong / tough
accept not brittle
•
hard
do not accept flexible
•
not (very) reactive
2
[5]
M15.
Quality of written communication:
for correct sequencing or linking of two
ideas or two points
annotate Q
or Q
1
any three from:
ignore superfluous statements
•
B is least energy efficient in terms
of cost (kJ per p), so A = C = D in
terms of cost or B is the most
expensive in terms of energy
efficiency
owtte
accept B is poor value for money / B is most
expensive
one is insufficient for mark
•
D is 1st, since gives only water as product or gives no harmful
products / gases or there are no pollutants
owtte
•
A is 2nd best, since produces CO2 owtte
•
C is 3rd, since gives SO2 owtte
if no other marks, then D A C B – based on
energy per kJ
per 100g only = 1 mark and Q mark if 2
ideas are linked
3
[4]
M16.
clay
1
limestone
1
water
1
[3]
M17.
(a)
hydrocarbons
1
(b)
evaporation
1
condensation
1
distillation
allow fractional distillation
1
(c)
lower and more
1
[5]
M18.
(a)
(i)
or
by (fractional) distillation
accept a description of the distillation
process (heat and how separation works) eg
heat and condense
accept boil / vapourise etc for heat
fractionation
1
(ii)
CO2
note the order of these products must be
correct
1
H2O
wrong way round = 1 mark
1
(b)
(i)
(hexane) has been broken down (into smaller hydrocarbons /
molecules)
1
accept (thermal) decomposition / cracked /
split / broken up owtte
(ii)
H
H
│
│
C
= C
│
│
H
H
accept CH2 = CH2
1
(iii)
water / hydrogen oxide / steam
accept H2O
1
(c)
candidates must include both sugar cane and crude oil in their
evaluation
and both an advantage and a disadvantage to gain full marks.
if they do not then the maximum mark is three
any four from:
advantages of using sugar
•
country has no wealth to buy (large quantities of) crude oil
not ‘expensive’ alone
•
country has limited technological development
or
underdeveloped / third world country
•
able / suitable climate to grow sugar cane
•
enough land to grow sugar cane / land cannot be used to
grow food / deforestation
•
sugar is a renewable source
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]
M19.
(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 / redorange
1
(iii)
(react) with hydrogen / H2 / hydrogenation
1
any one from:
•
heated / 60 °C
•
catalyst / nickel
1
[5]
M20.
(a)
(i)
contain enough metal to make it economical / worth
while to extract
1
(ii)
reduction
accept displacement
accept redox
1
(iii)
Fe + CO2
do not accept Fe2 / Fe4
1
correct balancing
accept multiples and halves
2Fe2O3 + 3C → 4Fe + 3CO2
allow Fe2 / Fe4 as ecf
1
(b)
Pure Iron
(in pure metal all the atoms are the same size and) able to slip /
slide over each
other – (property soft)
OWTTE
ignore references to molecules / particles
if they say ‘move’ both times, allow one
mark but ‘crack’ or ‘split’ is wrong..
1
Cast iron
(in cast iron) different sized atoms / larger atoms or structure is
distorted / disrupted
OWTTE
1
so it is difficult for layers of atoms to slip / slide over each other
OWTTE
1
(c)
any three from:
•
conserves / saves resources / metal ores
•
saves energy resources (used for extraction / processing)
accept cheaper / saves money
•
decreases waste materials
•
decreases a named pollution
do not accept acid rain
3
[10]
M21.
(a)
oxygen and nitrogen
1
20 – 21 % and 78 – 80 %
accept any two correct responses in the
correct space for one mark
1
(b)
(i)
acid rain
accept toxic gas or consequence of acid
rain
1
(ii)
idea of the removal or use of sulfur
dioxide gas (from the waste gases)
do not accept remove sulfur from coal
1
(iii)
oxygen
accept O2
1
water
accept H2O
accept hydrogen oxide / steam
1
(c)
any two from:
•
it’s a ‘greenhouse gas’ or increase greenhouse effect
accept action of a ‘greenhouse gas’
•
causes global warming or increase in the Earth’s temperature
•
sea-levels rise or flooding
•
climate change
•
(polar) ice-caps melt
•
extension of deserts
mention of ozone / acid rain / global
dimming = max 1 mark
2
(d)
idea trap / store / lock the carbon dioxide
1
in the oil reservoir or under the sea bed
do not accept ‘into the oil’ / ‘under the sea’
1
[10]
M22.
(a)
radioactivity (keeps the core hot)
accept half-life of radioactive elements has
proved the Earth is
older than 400 million years
accept the Earth is not cooling
do not accept fossil / rock evidence
1
(b)
any two from:
•
the shapes of the two continents fit together (like a jigsaw)
OWTTE\
do not accept the continents / they are the
same shape
•
the same type of rocks have been found
accept ‘rocks match’
•
the same fossils have been found
accept ‘fossils match’
•
rising magma rising through a gap under the Atlantic
2
(c)
any two from:
•
earthquakes
accept seismic waves
•
volcanoes
•
idea of distance between America and Europe / Africa is
increasing e.g.
continental drift
•
oceanic ridges
accept ocean floor spreading
•
formation of (new) mountain ranges
accept fold mountains or mountains
increasing in height
•
formation of (new) islands
•
magnetic stripes
•
tsunamis
2
[5]
M23.
(a)
(i)
poly(ethene)
accept polythene
1
(ii)
cracking
1
(iii)
hydrogen
1
(b)
(i)
bar labelled 9
1
bar drawn to correct height
1
(ii)
(boiling point) increases
1
(iii)
heat / evaporate (the crude oil)
accept separate by boiling point
1
cool / condense (hydrocarbons at different temperatures)
accept smaller molecules go to top / larger
molecules stay at bottom
accept fractional distillation for two marks or
distillation / fractionation for one mark
1
(c)
yes
any two from:
•
because plastic does not biodegrade or running out of space
for landfills or
land cannot be used for a long time
•
it provides heat energy
•
which can be used to generate electricity / heat homes or
greenhouses
•
any other advantage of burning
•
any other disadvantage of landfill
or
no
•
burning plastic produces carbon dioxide / carbon emissions /
toxic gases
accept landfill does not produce
carbon dioxide / carbon emissions
•
causes global warming / climate change / increase
greenhouse effect / global dimming / acid rain
•
any other disadvantage of burning
•
any other advantage of landfill
2
[10]
M24.
(a)
1 / one
1
3 / three
1
(b)
(i)
(wear safety) glasses / masks / gloves
accept do not handle hot objects / use
tongs or accept other safety points
such as, ‘tie hair back’
1
(ii)
calcium oxide
accept quicklime
1
(iii)
carbon dioxide / CO2 is given off
accept a gas is given off
1
(d)
(i)
any two from:
•
dust / atmospheric pollution
•
noise
•
eyesore
•
destroys habitats
•
(extra) traffic
•
any other named pollution or description of pollution
2
(ii)
any one from:
•
employment
•
increases local trade / makes money
•
future development of quarry recreation / park / lake /
reservoir
do not accept cheaper houses / land /
new roads
1
[8]
M25.
(a)
tungsten
1
has the high(est) melting point
accept that metals other than tungsten
are likely to melt
1
(b)
argon
1
is an unreactive gas
accept that gases other than argon are
reactive
accept that argon is a noble gas or in Group
0
1
[4]
M26.
(a)
pressing
1
(b)
(i)
water
accept hydrogen oxide / H2O
1
(ii)
filtration or description of this process
accept decanting or similar description of a
means of separating the seeds and skins
from the liquids
accept sieving
do not accept distillation / evaporation
1
[3]
M27.
(a)
made of one sort of atom
accept it is in the periodic table
accept it only has lithium atoms
1
(b)
nucleus labelled correctly
1
electron labelled correctly
1
[3]
M28.
(a)
any two from:
asks for cause therefore no marks for just
describing the change
must link reason to a correct change in a
gas
carbon dioxide has decreased due to:
accept idea of ‘used’ to indicate a decrease
•
plants / micro organisms / bacteria / vegetation / trees
•
photosynthesis
ignore respiration
•
‘locked up’ in (sedimentary) rocks / carbonates / fossil fuels
•
dissolved in oceans
ignore volcanoes
oxygen has increased due to:
accept idea of ‘given out / produced’
•
plants / bacteria / micro organisms / vegetation / trees
•
photosynthesis
ignore respiration
nitrogen increased due to:
accept idea of ‘given out / produced’
•
ammonia reacted with oxygen
•
bacteria / micro organisms
ignore (increase in) use of fossil fuels /
deforestation
2
(b)
(because methane’s) boiling point is greater than the average /
surface temperature or Titan’s (average / surface) temperature
is below methane’s boiling point
ignore references to nitrogen or water
1
any methane that evaporates will condense
accept boils for evaporates
accept cooling and produce rain for
condensing
1
(c)
(i)
bonds must be displayed correctly
ignore bond angles
1
(ii)
poly(propene) / polypropene / polypropylene
do not allow polypropane
any two from:
•
double bonds open up / break / become single(*)
•
propene molecules / monomers / they join / undergo addition
polymerisation(*)
1
•
form chains / long molecules(*)
(*)correct chemical equation gains 2 marks
ignore large
using monomer incorrectly max 2 marks
2
[8]
M29.
(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
•
acid rain (1)
accept effects of acid rain
ignore respiratory problems
caused by ( formation of) sulfur dioxide (1)
accept sulfur oxide
ignore sulfuric acid
•
global dimming (1)
ignore respiratory problems
caused by ( formation of) particles / particulates / fires /
smoke / carbon / pm 10 (1)
•
scarring of landscape (1)
caused by mining / quarrying of coal (1)
ignore ozone layer
max 4
(b)
any three from:
•
replant the trees / renewable / sustainable
ignore reusable
•
carbon dioxide is used by the trees / photosynthesis
accept trees absorb carbon dioxide as they
grow
do not allow respiration
•
it’s a (continuous carbon) cycle
accept ‘carbon dioxide goes back into the
air’
accept trees use CO2 which is released
when trees are burnt
•
no ‘new’ carbon (dioxide) is produced or
no locked up carbon (dioxide) is released
accept no carbon (dioxide) from fossil fuels
is produced
3
[7]
M30.
(i)
turns colourless
accept colour disappears
ignore fading
1
(ii)
any two from:
•
unsaturated fat content / healthiness about the same / similar
to maize
accept about the same number of double
carbon bonds as maize accept ‘a bit less’ for
similar
•
less unsaturated / less healthy than soya
accept fewer / less double bonds than soya
ignore ‘more saturated’
•
more unsaturated / more healthy than olive / palm
accept more double bonds than olive / palm
ignore ‘less saturated’
if no other mark awarded accept sunflower
oil has (about) the same result as maize oil
for 1 mark
ignore comments about saturated fats
2
[3]
M31.
(a)
any one from:
•
light(er) / less dense
ignore stronger
•
resistant to acids / alkalis / chemical
accept resistant to corrosion
1
(b)
any two from:
it must be clear
list principle applies
allow reverse argument
ignore reference to temperature
•
magnesium is more reactive than titanium
magnesium is above titanium in the
reactivity series
•
titanium is more reactive than carbon
•
magnesium is more reactive than carbon
•
magnesium is most reactive
•
carbon is least reactive
2
(c)
any three from:
it = titanium
ignore references to cost / easier /
usefulness alone or references to incorrect
processes
•
takes a long time to process
•
low abundance (of ore)
•
small amount produced
•
batch process used or blast furnace is continuous
•
more stages used to manufacture titanium
allow ≥ 3 / many / several
•
more energy used (per tonne of titanium)
allow high energy requirement
ignore references to temperature
•
magnesium / chlorine is expensive
•
labour intensive
3
[6]
M32.
(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]
M33.
(a) (an alloy) that can return to its original shape (after being
deformed / bent / twisted)
accept (on heating / cooling) it returns to its
shape
1
(b)
any two from:
•
brass / it is a mixture
accept brass / it is not pure
•
zinc changes structure / disrupts patterns or layers
•
copper metal atoms / layers able to slide over each other
accept zinc prevents atoms / layers sliding
over each other
2
(c)
(i)
oxygen / O2 / O
1
(ii)
lead remains (in furnace) because of its high boiling point
1
zinc boils / evaporates (out of furnace) because of its low
boiling point 1 if neither mark awarded then allow 1 mark for
different boiling points
ignore references to melting points
1
[6]
M34.
(a)
(i)
hydrogen
must be name
1
(ii)
a line of four or more ethene molecules joined to the original
two
with single bonds
at least two other ethene molecules joined
to the original two in a chain gains 1 mark
2
(b)
(i)
any two from:
•
non-biodegradable
accept remains a long time
•
landfill sites are filling up / limited
accept land / space used up
•
waste of a resource / could be recycled / reused
ignore references to tablets / animals
2
(ii)
any one from:
•
(two) different polymers / plastics / materials
•
need to be separated
•
limited collection points / many need to be collected
•
tablets may still be present
1
[6]
M35.
(a)
(i)
crushed
if line blank allow crushed circled in the box
1
(ii)
any one from:
•
‘costs’ less / cheaper
•
easier / faster
•
less complicated equipment
•
does not need heating / energy
•
distilling could decompose the oil
1
(b)
(i)
any one from:
•
do not mix / dissolve
•
(stay) separate
•
form layers
•
are immiscible
1
(ii)
mix
words must be in correct places
1
emulsion
1
[5]
M36.
(a)
tectonic
words must be in correct places
1
radioactive
1
(b)
(i)
any two from:
•
records not available / made / accurate
•
bodies not found
•
affected many islands / large area
2
(ii)
any two from:
•
cannot predict earthquakes / plate movement
•
(cannot) accurately (predict earthquakes)
•
(earthquakes / tsunamis) are random / not regular /
sudden
•
do not know what is happening below / in the Earth’s
crust / in the mantle
•
very slow / thousands of years build up of pressure
ignore references to technology / equipment
2
[6]
M37.
(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]
M38.
(a)
electron
words must be in correct position
1
nucleus
1
(b)
(i)
oxygen / O2
ignore air
1
(ii)
any one from:
•
(water) does not pollute
accept no harmful gas(es)
•
(only) water is produced
•
no carbon dioxide (is produced)
accept no greenhouse gas(es) / effect
•
no sulfur dioxide (is produced)
accept no acid rain
•
no nitrogen oxides (are produced)
•
no carbon / no particles (are produced)
1
[4]
M39.
(a)
any two from:
•
naphtha has a different / low(er) boiling point
accept different volatility
•
condenses at a different temperature / height / place in the
column / when it reaches it’s boiling point
•
different size of molecules
2
(b)
(i)
C10H22 → C6H14 + 2C2H4
allow multiples
1
(ii)
(hydrocarbon) heated / vapours
1
(passed over a) catalyst / alumina / porous pot
ignore other catalysts
1
(iii)
it / ethene is unsaturated or decane and hexane / they are
saturated
accept decane and hexane are alkanes /
CnH2n+2
or ethene is an alkene / CnH2n
or different homologous series / general
formula
1
ethene has a double (carbon carbon) bond or decane and
hexane have only
single (carbon carbon) bonds
accept ethene has a reactive double
(carbon carbon) bond for 2 marks
1
(c)
all bonds drawn correctly
1
(d)
economic argument against recycling
any one from:
•
poly(ethene) / plastic must be collected / transported / sorted /
washed
•
this uses (fossil) fuels which are expensive
1
environmental argument against recycling
any one from:
•
uses (fossil) fuels that are non-renewable / form
CO2 / CO / SO2 / NOx / particulates
ignore pollution / harmful gases / etc
•
washing uses / pollutes water
1
counter arguments
any two from:
•
collect / transport alongside other waste
•
use biofuels (instead of fossil)
•
landfill is running out
•
landfill destroys habitats
•
incinerators are expensive to build
•
saves raw materials / crude oil
•
saves energy needed to make new plastic
•
incinerators may produce harmful substances
•
incinerator ash goes to landfill
•
poly(ethene) is non-biodegradable
•
poly(ethene) can be made into other useful items
•
more jobs / employment for people
2
[12]
E4.
In part (a), although it was possible to gain both marks without doing
so, it was surprising that so few candidates mentioned the significance of
surface temperatures falling below 100 C.
In part (b) nearly all candidates understood that the process of
photosynthesis would remove carbon dioxide from the atmosphere.
Dissolving in sea water or the formation of carbonates was less
frequently mentioned.
E5.
Many examiners reported that this was the one question on the whole
paper that produced the poorest answers.
Some candidates were able to suggest distillation as the name of the
separation process, but very few offered the required answer of ‘fractional
distillation’. Hardly any candidates could suggest another hydrocarbon
gas.
It was disappointing to see so few candidates realising that carbon
dioxide and water are the products of combustion. ‘Methane oxide’ was
suggested by a fairly large number. There were equally few correct
answers giving carbon monoxide as being a product of incomplete
combustion.
E6.
Many candidates were unable to answer the question on organic
chemistry, gained only a mark for the last part by naming polythene and a
suitable use for it. The structural formulae for ethane and ethene were
usually omitted, reversed or incorrect. Where formulae were drawn, the
carbon and hydrogen were often reversed or five valent carbon atoms
were sometimes drawn.
That both organic compounds burn occurred only to those who were able
to get the whole question correct. Very few know how to distinguish
between an alkene and an alkane using bromine water.
E9.
Candidates’ knowledge of organic chemistry was often very limited. A
significant number of candidates only managed to score one mark, by
correctly drawing the structure of propane in part (c).
Part (a)was better known than part (b), where few could identify both
cracking and polymerisation.
Many candidates struggled to give a definition of saturated in part (d).
Part (e)was the least well answered part of this question. A common error
was to leave a double bond in the product. Although a variety of answers
were accepted the simplest answer is that given in the syllabus.
E10.
Double and Single Award
Paper 3 Foundation Tier
The basic ideas about reactions of hydrocarbons were not well known.
Although many candidates appreciated that using a catalyst would
increase the rate of cracking, ‘pressure’ and ‘oxygen’ were incorrectly
suggested. The word ‘only’ must be included when describing a
hydrocarbon as being ‘made up of carbon and hydrogen’. Many
candidates could determine the correct molecular formula for octane, but
some wrote the numbers as superscripts instead of subscripts. In part (c)
ethene was usually not known and cracking appeared more frequently
than the correct process of polymerisation.
Paper 6 Higher Tier
The basic ideas about reactions of hydrocarbons were not always well
known. Although ninny candidates did appreciate that using a catalyst
would increase the rate of cracking, ‘pressure’ and ‘oxygen’ were
incorrectly suggested. Candidates must include the word ‘only’ when
describing a hydrocarbon as being ‘made up of carbon and hydrogen’.
Many candidates could determine the correct molecular formula for
octane but some wrote the numbers as superscripts instead of
subscripts. In part (c) ethene was usually known but cracking was often
given instead of polymerisation.
E11.
Double and Single Award
Part (a) was answered well by the majority of candidates. Candidates
struggled in (b)(i) to use the correct scientific terms. Few candidates
suggested ‘boiling point’. Many thought incorrectly that petrol was at the
top of the column because it ‘is lighter’, ‘burns at a lower temperature’ or
‘has a lower melting point’. Generally candidates could not select the two
products of combustion for a hydrocarbon fuel. Many chose ‘SO2’ even
though in the stem of the question it stated that petrol contained the
elements carbon and hydrogen only.
E12.
Double and Single Award
Most candidates could not give a correct definition of an element - ‘made
up of atoms which contain the same number of protons’ or ‘made up of
only one type of atom’. Those candidates who stated that ‘an element
cannot be broken down’ usually forgot to add by chemical means. In part
(b) the majority of candidates knew the different properties of metals and
non-metals. Most candidates correctly identified sodium as being
unsuitable to make a cooking pot, however, few could give a correct
reason. Many stated incorrectly sodium ‘reacts with heat’, ‘is a non-metal’
or ‘is a poor conductor of heat’.
E13.
In part (i), the conversion of limestone into calcium hydroxide was
not well known. A number of candidates wanted to add water directly to
the limestone rather than heating it first. It is pleasing to note, however,
that a number of candidates not only described the two steps correctly
but also gave fully balanced chemical equations for the reactions.
Many of the candidates were able to gain one or two marks for the word
equation in part (ii). Common errors were stating chlorine instead of
hydrochloric acid and hydrogen instead of water. A number of the
candidates chose to write symbol equations rather than word equations.
Full credit was given for fully balanced symbol equation with all the
correct formulae. Nevertheless, candidates should be encouraged to
answer the question as set, since they often lost marks as a result of
incorrect formulae or balancing.
E14.
The answers to this question appeared to be centre dependent. Few
correct answers were seen to part (a) where many candidates thought
the oxide strengthened the pottery or made the glaze shiny. In part (b)
very few candidates could work out the formula of iron(III) oxide. In part
(c)(i) the equation was often incorrectly balanced. Part (c)(ii) was
generally well done although many thought that having a high boiling
point or being malleable were the key properties.
E15.
Few good answers were seen and ideas were often poorly
expressed. Few candidates mentioned energy efficiency in terms of cost
but referred to the gaseous products. The most common answer was
based on the energy of the fuels in kJ per 100g, which gave the correct
order. The mark for quality of written communication was only awarded
occasionally.
E16.
Foundation Tier
This was generally well answered although slaked lime was sometimes
given rather than limestone.
E17.
Foundation Tier
(a)
A fair number of candidates made no attempt at this section. They
either missed this part or did not know the answer. A good number
of candidates knew the correct response although a wide range of
incorrect answers was also seen including carbohydrates and fuels.
(b)
This part was usually very well answered.
(c)
Few candidates completed this part correctly. All permutations were
seen.
E18.
Most candidates knew how to separate ethanol and water, but not
all went on to condense the vapours. This was a more difficult equation,
but a significant number of candidates scored both marks. Cracking and
thermal decomposition are well known. The majority correctly completed
the structure of ethene and could name the other reagent needed to
make ethanol. Again, despite many good suggestions, few candidates
went on to score all four marks. Some candidates appeared to think that
two factors, applied to the two sources, was enough for all four marks.
The concept of a bio-fuel being carbon neutral seems to be well
understood. A surprisingly common error was to not read the question
correctly, and then to compare the use of ethanol and petrol as fuels.
E19.
Most candidates had an understanding of unsaturated and the
bromine test. Predictably, some did get the tests the wrong way round
and clear was misused as a description for colourless. The hardening of
oils was reasonably well known. Some candidates struggled to remember
the word chromatography.
E20.
Surprisingly, candidates found part (a) difficult. Few could explain
what an ore was. Acceptance of reduction, displacement and redox in
part(a)(ii) meant that many candidates got the mark, but a disappointing
number gave oxidation and even chemical reaction as the answer. A lot
of candidates could not balance the equation, with a large number writing
iron as Fe2.
Part (b) was less of a problem as most candidates answered this well.
There were a variety of possible correct responses to part (c). Few
candidates picked up all three marks although there were a lot of good, if
not complete, explanations. A minority blamed unrecycled iron for global
warming, global dimming, destroying the ozone layer and acid rain.
E21.
Surprisingly, most candidates only gained one of the marks in part
(a). Carbon dioxide was often given as one of the main gases and
several candidates were confused about the percentages of nitrogen and
oxygen present in the Earth’s atmosphere. The majority of candidates did
not appear to know that sulfur dioxide can cause acid rain.
In part (b)(ii), the responses given usually did not answer the question
asked; for example common incorrect answers were use gas-fired power
stations or don’t burn coal. Most candidates did not seem to understand
the word equation for burning methane in air.
In part (c) many candidates understand that carbon dioxide is a
greenhouse gas and contributes to global warming. Some candidates
appreciate the consequences of global warming. Again several
candidates incorrectly linked carbon dioxide to holes in the ozone layer.
The last part required candidates to use the diagram to explain this
method of preventing carbon dioxide from entering the atmosphere. Most
candidates gained at least one mark, although many candidates
incorrectly thought that the carbon dioxide could be stored to be used as
a fuel when the oil ran out.
E22.
There were poor answers to part (a), although some candidates did
gain credit for simply mentioning radioactivity.
The majority of candidates were only credited with one mark in part (b).
This was often because both parts of their suggestions were related to
the same evidence, that is, the two continents, and the sedimentary rocks
appear as if they had once been joined.
There were good responses to part (c). Most candidates were aware of
the link between plate boundaries and volcanoes and earthquakes.
E23.
Many candidates could not name the polymer made from ethene;
the most common incorrect answer was plastic. The rest of part (a) was
completed correctly by most candidates.
A surprising number of candidates did not attempt part (b)(i). Those who
did often lacked the accuracy required to draw the bar for the
hydrocarbon with nine carbon atoms. Some candidates forgot to label the
bar.
In part (b)(ii) most candidates appreciated the relationship between the
number of carbon atoms and the boiling point. Description of the
separation of fractions from crude oil was not well answered. Several
candidates thought that the process was cracking, although many
candidates did gain one mark for correctly stating that the process was
distillation.
In part (c) candidates could usually give part of an explanation for their
chosen method for the disposal of plastic bags but struggled to produce a
full explanation.
E24.
The majority of candidates understood the formula CaCO3 in part (a)
and almost all could suggest a reasonable safety precaution that should
be taken when heating limestone.
Most candidates were able to name quicklime / calcium oxide but found
part (b)(iii) more difficult.
E25.
The most common answer was tungsten, because, of all the metals
listed it had the highest melting point. However, aluminium and copper
were sometimes incorrectly chosen for their good electrical conductivity.
In part (b) most candidates did not know that argon is used in light bulbs
because it is unreactive or because it is a noble gas. Many candidates
incorrectly selected oxygen, for these wrong reasons, either because it
allows substances to burn or because it burns easily.
E26.
The question was answered correctly by most candidates. Where
errors were made, these were mostly in identifying the colourless liquid
as water. Sieving was a common, correct answer in (b)(ii) but distillation
and evaporation were not awarded marks.
E27.
The description of an element proved difficult for the majority of
candidates, but most were able to label correctly the parts of a lithium
atom.
E28.
Part (a) was well answered by the majority of candidates. The
decrease in carbon dioxide and increase in oxygen due to the evolution
of green plants was the most obvious and most common response, and
the more able candidates also linked this to photosynthesis. The role of
carbonate rocks and the oceans were less frequently put forward as
explanations for the decrease in the amount of carbon dioxide in Earth’s
atmosphere. The most common error was due to misreading the question
and answering in terms of modern day changes in the atmosphere due to
human activities. Relatively few candidates selected nitrogen as a gas to
write about.
Few candidates scored both marks on part (b). Lack of understanding of
negative temperatures often led to no marks being awarded, for example,
many candidates thought that Titan had a higher surface temperature
than the boiling point of methane. An analogy would be with the boiling
point of water and Earth’s average temperature. A small number of
candidates were able to gain the how rain forms mark even though most
envisaged methane perpetually above its boiling point on Titan. These
candidates showed an understanding of the processes of evaporation
and boiling and realised, but were unsure how, the methane condensed
to form rain.
Candidates, in general, attempted a structural formula in part (c)(i). Most
common errors were carbon skeletons, without hydrogen; having two or
no double bonds between carbons or two hydrogens plus a CH2 group on
the second carbon to get the correct number of H’s (CH2=CH2-CH2). A few
correctly drawn dot and cross diagrams were seen and given credit.
In part (c)(ii) some candidates understood the topic well, and understood
the concept of building a polymer from monomer units, with most of these
candidates gaining credit for joining them together to form a long chain
molecule. The majority of candidates were able to name the polymer as
polypropene, poly(propene) or polypropylene. Sometimes it was difficult
to decipher if the name of the product was poly(propene) or
poly(propane). Chemical names need to be clear and unambiguous,
particularly where a different spelling has a different meaning or shows a
lack of understanding.
E29.
The stem of part (a) did state that coal contains both carbon and
sulfur. However, a small number of candidates only addressed one of
them. Many candidates did not realise that a chemical reaction occurs
between the sulfur and the carbon in coal, with oxygen from air. Many left
them as carbon and sulfur and simply stated carbon and sulfur are given
off. Several candidates scored well on this question with carbon dioxide
causing global warming and sulphur dioxide causing acid rain as the
most common correct explanation. A common misconception is that a
greenhouse gas and the greenhouse effect are environmental problems.
The problem is global warming and its effects. References to the mining
of coal and the effect on the landscape were rare but, nevertheless,
gained credit. Comments such as bad for the environment or cause
pollution did not gain credit because they do not explain why burning coal
causes environmental problems.
The most common response to part (b) scored only two marks for saying
that although wood released carbon dioxide into the atmosphere when
burnt, the tree had taken in the same amount while it was growing and so
it is carbon neutral. Some went on to score the third mark by mentioning
that the trees were renewable or could be replanted or sustainable. Most
candidates did not appreciate that this neutrality will only work if new
trees are planted to absorb the carbon dioxide emitted, else the forest
would be completely cut down eventually. Very few candidates
appreciate that coal burning releases carbon that has been locked away
for millions of years. A common misconception was that wood does not
release any or as much carbon dioxide as coal. Additionally a worrying
number asserted that wood did not contain carbon so would not cause
any pollution. Some candidates thought that carbon dioxide was locked
away in trees meaning that when wood burns no carbon dioxide is
produced.
E30.
In part (i) the first part several candidates did not fully read or
understand the information given and had the oil changing colour.
Unfortunately, there is still a disappointing number of candidates who
equate clear to colourless.
Part (ii) asked for a comparison with the other oils. In this part sunflower
oil has neither the highest, nor the lowest, result, so a precise comparison
was needed with other, named, oils. An answer such as it’s in the middle
does not indicate if it is more or less unsaturated than say olive oil. It was
also possible to gain credit by working out the number of grams of
polyunsaturated fat per 100g of sunflower oil by comparing results with
the data in part (a). There was confusion by some candidates that more
unsaturated fat content means less saturated fat content.
E31.
The vast majority of candidates were awarded a mark for part (a),
mostly for selecting one of the properties, usually the 45% lighter idea
from the stem of the question.
Most candidates used the information provided and suggested a possible
reactivity series in part (b). Generally it appears that candidates do have
a good understanding of the reactivity series.
Many candidates misunderstood the part (c) and wrote in terms of the
better properties of titanium. The most common correct response was to
mention the smaller amount of titanium produced. Many candidates
stated incorrectly that this method of titanium extraction was expensive
because it was done by electrolysis, although some explained correctly
that the high cost was due to extraction of the magnesium by electrolysis.
Steel being an alloy also confused many candidates. Many simply
thought that the only expense of steel is in its production from iron,
forgetting the iron itself needs to be extracted from its ore. A frequent,
unsuitable answer, was Titanium is more expensive than steel because it
costs more to make. An explanation of the reasons for this extra cost was
required to gain any credit.
E32.
Foundation Tier
The information to answer part (a) was given in the table. Many
candidates gained credit for this question, usually for short carbon chain
length. Sometimes the word it was incorrectly used to refer to fuel oil,
although some candidates correctly stated that fuel oil has larger
molecules.
Information used from the table enabled most candidates to score marks
in part (b). Many candidates stated that there was a high demand for
petrol. Very few candidates mentioned that there was a short supply of
petrol or that there was not much petrol in crude oil.
Several candidates did not attempt part (c) and not many candidates
scored maximum marks. Few candidates were aware of the process of
cracking and its effect of reducing the length of the carbon chains.
Higher Tier
The information to answer part (a) was given in the table. The vast
majority of candidates gained credit for this question, usually for short
carbon chain length. Sometimes the word it was incorrectly used to refer
to fuel-oil, although some candidates correctly stated that fuel-oil has
larger molecules. A few, more able, candidates referred to the
intermolecular forces.
Information used from the table enabled most candidates to score marks
in part (b). Many candidates were able to compare the high demand for,
and short supply of, petrol in relation to fuel oil. Some candidates equated
the boiling points or height up the column to the energy need to extract
the petrol and the fuel oil without realising that the crude oil is heated to a
constant, high temperature to vaporise all of the fractions in the table.
Part (c) was well answered by most candidates. A large number of
candidates who scored maximum marks were aware that the process of
cracking would reduce the length of the carbon chains. Better answers
also described that cracking involved heating in the presence of a
catalyst. Many candidates were obviously confused with other processes:
heat to 60°C with a nickel catalyst was a frequent incorrect description of
the process. Although fractional distillation can be used to separate the
products of cracking, a number of candidates thought that this was used
to effect the reduction of hydrocarbon chain length.
E33.
Most candidates do not know the meaning of the term smart alloy
for part (a). Many gave the definition of alloy or stated that smart alloys
can bend easily into any shape. However, there was a small number of
candidates who did know that it was able to regain its original shape.
In part (b) most candidates did not gain any marks because they simply
repeated what was given in the stem of the question, that is, copper is
pure or brass is an alloy and contains copper and zinc atoms. Several
candidates knew that brass was a mixture but very few candidates
mentioned that the zinc atoms prevent the layers of copper atoms sliding
over each other.
For part (c)(i) a small majority of candidates understood that carbon
takes oxygen away from zinc oxide to leave zinc metal. Part (c)(ii) was
poorly answered because many candidates suggested that the zinc and
lead separate because lead melts before zinc. Those candidates who
realised that these metals were separated because they have different
boiling points gained one mark. The idea of separation by distillation was
not evident in the majority of candidates’ descriptions.
E34.
A significant number of candidates did not appreciate that
hydrocarbons contain carbon and hydrogen for part (a)(i). In part (a)(ii)
the candidates gaining both marks understood that a chain forms and
connected more than two extra molecules to the two already in the box.
Several candidates incorrectly drew pairs of molecules or drew lattice
structures.
Most candidates scored at least one mark in part (b)(i), usually by stating
that the tablet container was non bio-degradable. Landfill sites filling up
was another popular correct suggestion with only a few candidates
appreciating that it was a waste of a resource or that it could be recycled
or reused.
In part (b)(ii) only a few candidates seemed to realise that it would be
difficult to recycle the tablet container because it was made of two
different polymers and therefore these polymers first needed to be
separated.
E35.
The majority of candidates realised that the fruits or seeds of plants
are crushed to extract the vegetable oil in part (a)(i). Most candidates did
not gain a mark in part (a)(ii) because they described the process of
filtering rather than suggesting why filtering is better than distillation. The
common correct suggestions were that filtering is cheaper or quicker or
does not require heating or energy.
Most candidates gained the mark in part (b)(i), the majority just stating
that the vegetable oil and water are separate. Again most candidates
gained full marks in part (b)(ii) for understanding that egg yolk would
cause the vegetable oil and water to mix and form an emulsion.
E36.
In part (a) most candidates knew that earthquakes are caused by
movement of the Earth’s tectonic plates. Few candidates knew that the
movement of the tectonic plates is caused by heat released from natural
radioactive processes.
The most common correct suggestion made in part (b)(i) was that some
of the bodies had not been found for a variety of reasons. Very few
mentioned that the tsunami covered a huge area or that there may be no
accurate records of people or bodies. Some candidates misunderstood
the question and explained how an estimate could be or was made.
In part (b)(ii) candidates were not always clear as to whether they were
referring to the earthquake or the tsunami. Not many candidates
managed to gain both marks here but many achieved a mark for
statements related to the fact that earthquakes are not predictable.
Several candidates thought that scientists were unable to detect or
predict this earthquake because it occurred under the sea or ocean.
E37.
For part (a)(i) most candidates knew that it is sulfur dioxide that
causes acid rain. Most candidates did not know that smoke particles
could cause global dimming in part (a)(ii).
In part (a)(iii) many candidates gained one mark for stating that it was the
greenhouse effect or global warming that may cause climate change.
However, candidates are confused between the greenhouse effect and
the hole in the ozone layer. Only better candidates made reference to
carbon dioxide.
Both bars were usually well drawn in part (b). The coal bar was
sometimes drawn incorrectly, usually at 31 or 34 instead of 32.
E38.
The majority of candidates could correctly label the diagram of a
hydrogen atom in part (a).
In part (b)(i) the majority of candidates understood that oxygen was
reacting with hydrogen to form water.
Many candidates managed to gain the mark in part (b)(ii), however, there
were many vague answers, such as, it does not harm the environment;
hydrogen is environmentally friendly, which did not gain credit.
E39.
In part (a) descriptions of separating naphtha by fractional distillation
were often poor because of the common misconception that the fractions
are separated as they evaporate, rather than as they condense.
In part (b) most candidates can balance equations, a lot cannot.
Cracking is well understood, although a significant number concentrated
on what happens to the molecules rather than how the process is carried
out. A number of candidates appeared to be describing fractional
distillation rather than cracking. Most understood the difference between
alkanes and alkenes, although some candidates only mentioned the
difference in chain length.
In part (c) most candidates gave the correct structure of ethene. In part
(d) few candidates structured their answers in this part. Many did not
base their arguments on the ‘chosen’ recycling option. It was often
impossible to tell what the candidates were arguing in favour of and
against. A number just gave the benefits of recycling, with no
counterarguments. This part was marked as a whole, crediting the
marking points wherever they were given in a candidates answer.
Although most candidates scored some marks on this question, few
scored full marks.
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