C1B Mark Scheme for AQA Science B

For use with the specimen C1B exam paper.

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Chemistry Specimen Paper C1B ­ Nov 2010
Mark Scheme (updated November 2010)
Qs Answer Accept/Reject Mk
1a CaCO3 -> CaO + CO2 CaOH2 ­ no 6
CaO + H2O -> Ca(OH)2 brackets -1 for
Ca(OH)2 + CO2 -> CaCO3 + H2O each time used
CaCO3 = CaO +
CO2 ­ equals
sign should not
be used -1 for
each time used
1b Cement = mixture of limestone, clay, If any 2
and other minerals which are heated ingredient is
and then ground into fine powder. missed out, or
Concrete = adding stones or crushed extra
rock to mixture of water, cement and ingredient
sand added, take
out 1 mark.
If no difference
is highlighted,
subtract full
1c Iron is extracted using blast furnace = Equations do 4
large container made of steel. Hot air not count for
blown into furnace, making coke burn, marks (ref
thus heating furnace. Carbon monoxide Q1D).
used as reagent to react with iron Must explain
oxide, removing oxygen reducing it to process ­ full
molten iron. process not
explained -2
are not
accountable for
Limestone to
impurities = 1
1d C +O2 -> CO2 Incorrectly 6
CO2 + C -> 2CO balanced takes
Fe2O3 + 3CO -> 2Fe + 2CO2 away 2 marks.
If incorrectly
balanced due

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equation or
symbol, e.g.
FeO and not
Fe2O3, take
away one mark.
1e Alloy: metals that contains other Mixup of 2
elements, usually for more desired definitions
properties means NO
Ore: enough metal or metal compound marks.
in a rock to make it worth extracting Accept shorter
the metal version for 1
mark only.
1 mark per
1f Titanium forms carbon compounds, and Mentioning 2
so would not be displaced.…read more

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Cracking: breaking a molecule apart One mark per 4
using heat. correct
Distillation: evaporation, and definition.
condensation in succession to purify Examples
liquids account for no
Refining: removing impurities marks.
Unsaturated Hydrocarbon: hydrocarbon,
which contains a double carbon-carbon
2b Unsaturated ­ contains double carbon One mark for 3
bond. Can react with other elements to answer, two
form other compounds. for
description. If
answer is not
explained, max
mark is two.…read more

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Example = 1
3d Emulsifier: a substance that stops oil Example 2
and water from separating out into accounts for
layers. mark if shown.
Student can
still gain full
marks without
3e Salad cream is thicker than water. Allow any 2
Salad cream is heavier than oil. other answer
Salad cream has taste unlike water. that is
3f Biodiesel is name given to any fuel Full 4
made from vegetable oils.…read more

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Tectonic movement is caused by Explanation is 5
convection currents that push tectonic worth just 1
plates over the surface of the Earth. MARK!
Pencil drawn
diagram = 1
currents shown
= 1 marks.
2 convection
currents shown
at least = 1
annotation = 1
4c Existence for Pangaea: Mentioning 4
Mountains each = 1 mark
Volcanoes/ Earthquake regions each.
Shape of the continents `fit' Mentioning 2-3
Fossil evidence in little detail
= 4 marks.…read more

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Carbon sinks:
Fossil fuels locked away ­ BUT
now we're releasing this lock
back into the atmosphere
Forests ­ nature ­ plants for
Rocks absorb CO2
21 Pass mark = 53/74 72% B 74
30/74 41% D
47/74 64% C
53/74 72% B
60/74 81% A
69/74 93% A*
This marking criterion is based on the AQA Chemistry 1B (Paper B) guidelines
for Higher Tier Triple and Double Award students.…read more


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