GCSE Science
C3: Chemicals in our lives – risks and benefits
Study Pack
Name:
Science Group:
Teacher:
Peer/self-assessment:
1 = Exemplary answer, excellent understanding, all points correct, S.G.P. correct
2 = Good answer, solid understanding, most points correct, S.G.P. mostly correct
3 = Unsatisfactory, mixture of correct & incorrect points, S.G.P. mixed quality
4 = Inadequate, poor understanding, incorrect points, S.P.G incorrect
C3.1 What were the origins of minerals in Britain that contribute to our
economic wealth?
 I understand that geologists explain most of the past history of the
surface of the Earth in terms of processes than can be observed today
 I understand that movements of tectonic plates mean that the parts of
ancient continents that now make up Britain have moved over the surface
of the Earth
 I understand how geologists use magnetic clues in rocks to track the very
slow movement of the continents over the surface of the Earth
Create a poster which shows the changes in the tectonic plates in the
globe over time. Annotate the diagrams to show how scientists linked their
observations with the theory of plate tectonics (use how magnetic rocks of
different ages and directions proved that Scotland was once 5 separate
pieces)
 I understand that the movements of continents means that different rocks
in Britain formed in different climates
 I understand how processes such as mountain building, erosion,
sedimentation, dissolving and evaporation have led to the formation of
valuable resources found in England including coal, limestone and salt
 I understand how geologists study sedimentary rocks to find evidence of
the conditions under which they were formed, to include:
-fossils
-shapes of water borne grains compared to air blown grains
-presence of shell fragments
-ripples from sea or river bottom
 I understand that chemical industries grow up where resources are
available locally, e.g. salt, limestone and coal in north west England
1) What is sedimentary rock? Write down 5 steps in which it is formed,
using these words in order: transportation, deposition, sedimentation,
fossilisation & erosion.
2) Make a timeline to show how climate changed over the years in the
North-West of England to allow salt, limestone & coal to form.
3) Research on the importance of Limestone, Salt & Coal in the old
chemical industry (or industrial revolution) in the UK.
4) Make a leaflet for geologists with diagrams & annotations showing the 4
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different conditions in which sedimentary rocks were formed (from the
above list)
C3.2 Where does salt come from and why is it so important?
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I understand the importance of salt (sodium chloride) for the food
industry, as a source ofchemicals and to treat roads in winter
I can recall that salt can be obtained from the sea or from underground
salt deposits
I understand how underground salt can be obtained by mining, or by
solution in water
I understand why the method used to obtain salt may depend on how the
salt is to be used
I understand how the methods of obtaining salt can have an impact on the
environment
1) Make a spider diagram of all the uses of salt (sodium chloride) in
everyday life
2) Draw a diagram to explain how salt can be produced by mining
underground deposits & by solution mining
3) Compare the advantages & disadvantages of both methods of salt
extraction
 I understand the advantages of adding salt to food as flavouring and as
a preservative
 I can recall the health implications of eating too much salt
 I can evaluate data related to the content of salt in food and health
 I can recall that Government departments, such as the Department of
Health and the Department for Environment, Food and Rural Affairs,
have a role in:
-carrying out risk assessments in relation to chemicals in food
-advising the public in relation to the effect of food on health
1) Make a table listing the salt content (as a percentage of your daily
intake) on food labels from the following 5 foods in your home (you
may replace with 5 others): ketchup, cereal, cheese, butter, baked
beans. Compare the salt content in these foods and rank them from
healthiest to least healthy.
2) Explain what a risk is and list the low & high risks of eating too much
high-salt foods.
3) Research on the above 2 methods which the government uses to advice
the public about reducing their salt intake
C3.3 Why do we need chemicals such as alkalis and chlorine and how do
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we make them?
 I can recall that, even before industrialisation, alkalis were needed to
neutralise acid soils, make chemicals that bind natural dyes to cloth,
convert fats and oils into soap and to manufacture glass
 I can recall that traditional sources of alkali included burnt wood or stale
urine
 I understand that alkalis neutralise acids to make salts
 I can recall that soluble hydroxides and carbonates are alkalis
 I can predict the products of the reactions of soluble hydroxides and
carbonates with acids
 I understand that increased industrialisation led to a shortage of alkali in
the nineteenth century
1) Write a paragraph explaining interlinking acids, alkalis, universal
indicator, pH, litmus paper, neutralisation reaction, salt, water
2) Describe how alkalis are extracted from ashes of plants (e.g. potash &
soda)
3) Complete the table below:
Uses of alkalis
Alkalis involved &
their sources
Description
Making soap
Neutralising soil
Making glass
Dyeing fabrics
4) What is the difference between bases & alkalis? Give 2 examples of
each
5) Describe how the demands of the industrial revolution (e.g. for
ironworks, glass, pottery, textiles, soap making) led to supplies of
alkalis running out
6) Write 3 word equations using any of the acids & alkalis from the table
below, to show what products would be produced. Use the generic word
equations below:
Alkali (hydroxide) + acid  salt + water
Alkali (carbonate) + acid  salt + carbon dioxide + water
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Common alkalis
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I understand that the first process for manufacturing alkali from salt and
limestone using coal as a fuel caused pollution by releasing large volumes of
an acid gas (hydrogen chloride) and creating great heaps of waste
(“galligu”) that slowly released a toxic and foul smelling gas (hydrogen
sulfide)
I understand that pollution problems can sometimes be solved by turning
wastes into useful chemicals
I understand that oxidation can convert hydrogen chloride to chlorine, and
that the properties of a compound are completely different from the
elements from which it is made
1) Briefly describe LeBlanc’s method for making sodium carbonate from
salt & sulphuric acid
2) How were the waste products hydrogen sulphide and hydrogen chloride
recycled & reused through William Gossage’s method?
3) Explain using a word equation how alkali industries profited from
producing chlorine (used as a bleach by textile industries) from
hydrochloric acid.
4) Compare the properties of chlorine to hydrochloric acid, including
solubility, colour & use as a bleaching agent.
 I can recall that chlorine is used to kill microorganisms in domestic water
supplies and as a bleach
 I understand how the introduction of chlorination to treat drinking water
made a major contribution to public health
 I can interpret data about the effects of polluted water on health and the
impact of water treatment with chlorine to control disease
 I understand that there may be disadvantages of chlorinating drinking
water, including possible health problems from traces of chemicals formed
by reaction of chlorine with organic materials in the water
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1) Explain how the likelihood of dying from typhoid fever in the USA
changed over the years (the role of chlorine in treating water, you will
need the maximum number of deaths before chlorination, how many
years it took for it to be halved, the correlation between chlorination
of water & number of deaths).
2) There are fears that
chlorine reacts with
organic compounds in
water to make
carcinogenic or toxic
disinfectant by-product
(DBP). But this is far
less likely than death by
a car accident. Compare
& contrast the
advantages &
disadvantages of using
chlorine to treat water.
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I understand that an electric current can be used to bring about
chemical change and make new chemicals through a process called
electrolysis
I can recall that chlorine is now obtained by the electrolysis of salt
solution (brine)
I can recall examples of important uses by industry of the sodium
hydroxide, chlorine and hydrogen produced by electrolysis of brine
I can interpret data about the environmental impact of the large scale
electrolysis of brine.
1) Label and annotate the electrolysis diagram below to show how
hydrogen, chlorine & sodium hydroxide are produced from the
electrolysis of brine (aqueous sodium chloride). Label the anode,
cathode, electrolyte, membrane cell
2) Write a word reaction for the electrolysis of brine
3) List the uses & risks of chlorine, sodium hydroxide & hydrogen
4) The graph below monitors the blood mercury concentration in Aboriginal
Canadians over the years, whose diet consists of local fish and
wildlife. A paper company (using mercury for electrodes) was
established close to the rivers which aboriginals fish from, and a lot
of mercury waste was dumped over the years. The World Health
Organisation (WHO) states that the acceptable mercury level in the
blood should be less than 20 parts per billion (ppb) and less than 6ppb in
hair samples. Analyse the graph to determine if the risk of mercury
poisoning is high, and what might have happened over the years to result
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in the decline in blood mercury levels.
C3.4 What can we do to make our use of chemicals safe and sustainable?
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I understand that there is a large number of industrial chemicals with
many widespread uses, including consumer products, for which there is
inadequate data to judge whether they are likely to present a risk to the
environment and/or human health
I understand that some toxic chemicals cause problems because they
persist in the environment, can be carried over large distances, and may
accumulate in food and human tissues
Make a flowchart or classification key showing how decisions are made
about the levels of risk associated with the following chemicals:
chlorofluorocarbons (CFC), Sodium Laureth Sulphate, Sodium hydroxide,
Sullphur Dioxide, Mercury, and Propane. You should annotate your
classification key to indicate how you decided the level of risk to humans
& the environment (use 2nd bullet point)
 I can recall that PVC is a polymer that contains chlorine as well as carbon
and hydrogen
 I understand that the plasticizers used to modify the properties of PVC
can leach out from the plastic into the surroundings where they may have
harmful effects
PVC comes in 2 forms; plasticised and unplasticised. Plasticisers are small
moleculs which sit in between the polymer chains and disrupt the
intermolecular forces, making the structure irregular, weaker & softer.
1) Make a spider diagram of uses of PVC
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2) Why is plasticised PVC banned from use in children’s toys in Europe &
the USA? Explain using leaching in your answer
3) Research on the risks of PVC to health, food, environment and from
burning it.
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I understand that a Life Cycle Assessment (LCA) involves consideration of
the use of resourcesincluding water, the energy input or output, and the
environmental impact, of each of these stages:
o making the material from natural raw materials
o making the product from the material
o using the product
o disposing of the product
When given appropriate information from a Life Cycle Assessment (LCA), I
can compare and evaluate the use of different materials for the same
purpose
Design an LCA flowchart on a paper cup and another on a plastic cup.
Consider the amount of natural resources needed, energy demand, how
much water & air will be used and whether it is an environmentally
friendly product to produce. Make a conclusion from your findings about
whether it is better to use a plastic cup or a paper cup.
Grades A* - C
(Higher)
All statements shown in bold & italic as well as all statements shown
in normal type.
Grades C – G
(Foundation)
All statements shown in normal type.
R.A.G. each of the statements to help focus your revision:
R = Red: I don’t know this
A = Amber: I partly know this
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G = Green: I know this