Chemistry C1 Example Extended Response Questions
Six mark questions will appear on both the foundation and higher tier papers. Five marks
will be available for the content of the answer and one mark available for the quality of
written communication (QWC). A high level answer will be well organised and demonstrate
accurate spelling, punctuation and grammar.
Topic 1 – Higher
The composition of the atmosphere is different from the early atmosphere. Describe how
the proportion of oxygen, carbon dioxide and water vapour has changed from the early
atmosphere to the present day. Suggest why scientists might be uncertain about this
information.
Marking points
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Early atmosphere mostly carbon dioxide
Early atmosphere virtually no oxygen
Early atmosphere more water vapour than today
Green plants evolved and produced oxygen, now 21%
Carbon dioxide levels have fallen, only 0.04%
Water vapour cooled and condensed
Evidence has been found in rocks/ice core formed many years ago
Measurements are difficult to make precisely
Scientists were not there to take measurements millions of years ago
Any 5 points + 1 QWC mark. To score 6 marks the limitations of the evidence must be
commented on.
Topic 2 – Foundation
Rocks can be sedimentary, metamorphic and igneous. Examples of these three types
include;
 Limestone – sedimentary
 Slate – metamorphic
 Granite – igneous
Describe, in as much detail as possible, how the rocks were formed and how they differ
from each other in appearance.
Marking points
Limestone
 Layers of sediment laid down
 Over millions of years pressure squeezes out the water
 Sediments are cemented together
Slate
 Heat and pressure over long periods
 Changes sedimentary and igneous rocks
Granite
 Formed when molten lava or magma cools
Appearance
 Limestone has randomly shaped particles
 Limestone contains fossils
 Slate has small crystals
 In slate the crystals are arranged in layers
 Granite has interlocking crystals
 In granite the crystals are randomly arranged
Any 5 points + 1 QWC mark. To score 6 marks all three rock types must be commented
on.
Topic 3 - Foundation
There are several different brands of indigestion tablets which contain calcium
carbonate.
The calcium carbonate neutralises excess acid in the stomach.
In an investigation, dilute hydrochloric acid was added to an indigestion tablet
until the tablet had completely reacted. The volume of hydrochloric acid required was
measured.
The experiment was repeated with four different brands of tablet, A, B, C and D.
The cost of one tablet and the results of the experiment are shown in the table.
Evaluate the results of the experiment to find the effectiveness and value for money of each
indigestion tablet. (6 marks)
Marking points
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the more acid neutralised the more effective the tablet
order is D, B, A, C
cost must also be taken into account
order per penny is A, D, B, C
most effective per tablet is D
best value tablet is A.
5 points + 1 QWC mark.
Topic 5 - Foundation
Fuels used in gas fires contain methane.
The complete combustion of methane produces carbon dioxide and water.
In faulty gas fires, incomplete combustion of methane can take place.
Discuss the problems that can be caused by both the complete and incomplete combustion
of methane in a gas fire. (6marks)
complete combustion:
 gives carbon dioxide
 leads to global warming
incomplete combustion:
 carbon monoxide is formed
 carbon monoxide is toxic/toxic gas formed
 carbon monoxide combines with haemoglobin
 oxygen cannot combine with haemoglobin
 carbon monoxide is odourless/colourless
 people are not aware of breathing it in
 carbon (soot) blocks chimneys/aggravates asthma
 may give out less energy.
Any 5 points + 1 QWC mark.
Topic 5 - Higher
Some biofuels are made from plants.
The biofuel ethanol is often made from sugar cane or sugar beet.
Petrol is a fossil fuel that is made from crude oil.
A small number of filling stations sell biofuels as well as petrol.
Evaluate the advantages and disadvantages of using biofuels instead of petrol as a
fuel in cars. (6 marks)
Marking points
An evaluation including references to the following:
e.g. the advantages of biofuel making specific references to:
 biofuel is renewable, petrol is finite
 production uses CO2 so ‘carbon-neutral’, reduction of greenhouse emissions
 petrol gives ‘greenhouse effect’
may also refer to impact in the everyday world such as:
 environmentally friendly
 save drivers money
 needs increased labour so helps to tackle world poverty
e.g. the disadvantages of biofuel making specific references to:
 need land to grow crops
 losing land to grow food
 low availability so low impact
more sophisticated responses may include comment on:
 biodiversity – loss of habitats
 first generation biofuel not sustainable
 burning of some crops can produce as much in carbon emissions
Each point 1 mark up to a max of five + 1 QWC mark. Advantages and disadvantages must
be included.
Topic 5 - Higher
Alkenes can be used to make polymers (plastics).
Polymers are useful materials.
Waste polymers can be recycled, burned or buried in landfill sites.
Evaluate these three methods of dealing with waste polymers. (6 marks)
Marking points
e.g recycling polymers referring to:
 using materials/not wasting them/environmentally friendly
 hard to recycle some types of plastic
 requires public cooperation and sorting
e.g. burning polymers referring to:
 dangers of burning polymers – toxic fumes
 dangers including fire hazard
 dangers including references to poisons such as hydrogen cyanide
e.g. burying polymers referring to:
 non–biodegradable polymers will continue to exist in the landfill sites
Each point up to a max of 5 + 1 QWC mark. To score 6 marks all three disposal methods
must be commented on.