Summary of each specification point for Edexcel C1.

1. The first gases came from the eruption of Volcanoes and formed the Earth’s early
atmosphere.
The main gases in the early atmosphere were:
• Lots of carbon dioxide
• Some nitrogen
• Little or no oxygen
• Water vapour
• Ammonia
Volcanoes release these gases today (and so scientists think the same processes
operated in the past).
C1.1 The Early atmosphere
The oceans were formed from the
condensation of the water vapour to
make liquid water.

2. C1.2 a changing atmosphere.
A simple carbon cycle
The level of carbon dioxide in the atmosphere is
maintained by several processes, photosynthesis,
respiration and combustion
Green plants remove carbon dioxide from the
atmosphere by photosynthesis. Respiration and
combustion both release carbon dioxide into the
atmosphere.
These processes form a carbon cycle in which the
proportion of carbon dioxide in the atmosphere
remains about the same.
Carbon dioxide fell because:
• Some carbon dioxide
dissolved into the oceans.
• Some was absorbed by
marine creatures who stored
it tin their shells as calcium
carbonate which later formed
carbonate rocks.
As the number of plants
increased, the oxygen levels rose
through photosynthesis. These
plants absorb carbon dioxide too.
Carbon dioxide levels fell
Oxygen levels rose

3. C1.4 The atmosphere
today.
Changes in the atmosphere occur
through;
Natural activities:
• Volcanic activity can lead to a rise in
sulphur dioxide; lightening can lead
to a rise in nitrogen oxides.
Human activity:
• burning fossil fuels can lead to an
increase of carbon dioxide, carbon
monoxide and sulphur dioxide.
• Deforestation lead to an increase in
carbon dioxide; burning trees
releases carbon dioxide
(combustion), fewer trees to
photosynthesise and absorb carbon
dioxide; engines and furnaces
release nitrogen oxides.
• Farming: increasing numbers of
cattle and rice fields can lead to an
increase of methane.
How do scientists use rocks to work out the composition of the
Earth’s early atmosphere?
Analyse the minerals in them and look for oxides. As more oxygen was
present, more oxide mineralswere formed.
Gas Formula % in dry air
Nitrogen N2 78
Oxygen O2 21
Argon Ar 0.9
Carbon
Dioxide
CO2 0.04
other trace
Our atmosphere today…

4. C1.5 Rocks and their Formation
Igneous Rocks
• Example – granite.
• Formed by the solidification of
magma or lava
• They contain crystals whose
size depends on the rate of
cooling.
• Quick cooling = small crystals
• Fast cooling = large crystals
metamorphic – A rock changed by pressure and heat.
sedimentary – A rock formed by the deposition of sediments.
thermal decomposition – The breakdown of a compound into
simpler substances by heating.
electrolysis – The use of electricity to split a compound.
granite – A type of igneous rock that is harder than limestone and
marble.
igneous – A rock formed from cooled magna.
limestone – A type of sedimentary rock containing calcium
carbonate.
limewater – A limestone product made by fully dissolving
quicklime in water. It is used to test for carbon dioxide.
marble – A type of metamorphic rock that is harder than limestone
but softer than granite
Sedimentary rocks
• Sedimentary rocks contain fossils
• They are formed from compaction of
layers of rock over a long time.
• They are not as strong as other rocks so
erode easily.
• Examples - chalk and limestone
Metamorphic Rocks
• Example – marble
• Formed when heat or
pressure is applied to other
rocks.
• Marble is formed from
chalk or limestone being
heated and pressurised.
Limestone, chalk and marble are all forms of
calcium carbonate and exist in the Earths
crust.

5. C1.6 Limestone
Limestone is made of calcium carbonate (CaCO3)
It is used in:
– Building materials- glass, cement, concrete
– Improving the pH of acid soil
Thermal Decomposition of Calcium Carbonate
When metal carbonates are heated they break down
into a metal oxide and carbon dioxide is given off
Copper carbonate  copper oxide + carbon dioxide
CaCO3 CaO + CO2
Problems associated with quarrying:
Economic - money
Social – the people
Environmental - pollution
Limestone is heated with clay to make cement
Cement is added to sand and water to make mortar
Cement is added to sand, aggregate and water to make
concrete
Advantage of quarrying…jobs and valuable building
resources.
The advantages and disadvantages of quarrying.

6. C1.7 Thermal decomposition
Ease of thermal decomposition of metal carbonates:
• Most difficult to decompose is sodium carbonate (10000C), calcium carbonate (8250C), zinc
carbonate (3000C) and copper carbonate (2000C).
• Copper carbonate will start to decompose to form carbon dioxide and copper oxide. The
reaction will absorb some of the heat from the fire. The carbon dioxide can help to put out
the fire by reducing the amount of oxygen available for combustion.
• The mass of reactants do not change, the particles just get rearranged.
• The atoms take part in a chemical reaction they are very small.
• When calcium hydroxide is dissolved in water it makes Limewater.
Copper carbonate  copper oxide + carbon dioxide
CaCO3(s)  CaO(s) + CO2(g)
Copper carbonate  copper oxide + carbon dioxide
Zinc carbonate  zinc oxide + carbon dioxide
Breaking down with heat

7. C1.8 Chemical
reactions
Word equations
A word equation gives the names of the substances
involved in a reaction. For example:
copper + oxygen → copper(II) oxide
Copper and oxygen are the reactants, and copper(II)
oxide is the product.
Precipitation reactions
1) A simple example of conservation of mass is a
precipitation reaction.
2) Transition metals form coloured compounds with other
elements. Many of these are soluble in water, forming
coloured solutions. If sodium hydroxide solution is then
added, a transition metal hydroxide is formed. These are
insoluble. They do not dissolve but instead form solid
precipitates. As all the reactants and products remain in
the sealed reaction container then it is easy to show that
the total mass is unchanged.
copper sulfate + sodium hydroxide → copper
hydroxide + sodium sulfate
CuSO4 + 2NaOH → Cu(OH)2 + Na2SO4

8. C1.9 Reactions of
Calcium
Compounds
Neutralising acids with limestone
1. Calcium compounds that neutralise acids:
– Calcium carbonate (CaCO3)
– Calcium oxide (CaO)
– Calcium hydroxide (Ca(OH)2)
2. Uses of these alkalis
1. Farmers neutralise soil
2. Power stations use wet powdered CaCO3 to neutralise acidic waste gases like Sulfur dioxide and
nitrous oxides. ( below is the equation for sulfur dioxide production)
S (g) + O(g) SO2 (g)
Keywords
• Neutralisation reaction - reaction in which a base or an alkali reacts with
an acid.
• Limewater – Solution of calcium hydroxide. It is used to test for the
presence of CO2 as it turns from colourless to cloudy.
Making Limewater
1. Heating limestone - Calcium carbonate (CaCO3) turns it into Calcium oxide (CaO)
CaCO3 (s) CaO(s) + CO2 (g)
2. Adding water to CaO – vigorous reaction that creates calcium hydroxide (crumbly solid)
CaO(s) + H2O (l) Ca(OH)2(s)
Testing for CO2 - limewater turns cloudy/milky as calcium carbonate forms.
Ca(OH)2(s) + CO2 (g) CaCO3 (s) + H2O (l)
NB – large quantities of CO2 will dissolve to form an acid. This reacts with the CaCO3 making it
colourless again!

9. 1.10 indigestion
Indigestion remedies contain substances to neutralise excess stomach acid.
• When an acidic compound dissolves in water it produces hydrogen ions, H+. These ions are
responsible for the acidity of the solution.
• When an alkaline compound dissolves in water it produces hydroxide ions, OH−. These ions are
responsible for the alkalinity of the solution.
• Acids react with alkalis to form salts. These are called neutralisation reactions. In each reaction,
water is also formed:
Acid + alkali → salt + water
Example
Hydrochloric acid + sodium hydroxide → sodium chloride + water
HCl + NaOH → NaCl + H2O
• Hydrochloric acid contains hydrogen ions and chloride ions dissolved in water.
• Sodium hydroxide solution contains sodium ions and hydroxide ions dissolved in water.
Hydrochloric acid is produced in the
stomach to kill bacteria and to help
digestion.
Hydrochloric acid produces chloride salts e.g. calcium chloride
Nitric acid produces nitrate salts e.g. calcium nitrate
Sulfuric acid produces sulfate salts e.g. calcium sulfate

10. C1.11Neutralisation
• You need to be able to describe the reactions of hydrochloric acid and sulfuric acid with
metal hydroxides, metal oxides and metal carbonates.
Metal hydroxides
• Metal hydroxides, such as sodium hydroxide, usually dissolve in water to form clear,
colourless solutions. When an acid reacts with a metal hydroxide, the only products formed
are a salt plus water. Here is the general word equation for the reaction:
acid + metal hydroxide → a salt + water
• there is a temperature rise
• the pH of the reaction mixture changes
Metal oxides
• Some metal oxides, such as sodium oxide, dissolve in water to form clear, colourless
solutions. Many of them are not soluble in water, but they will react with acids. Copper(II)
oxide is like this. When an acid reacts with a metal oxide, the only products formed are a salt
plus water. Here is the general word equation for the reaction:
acid + metal oxide → a salt + water
Metal carbonates
• Although sodium carbonate can dissolve in water, most metal carbonates are not soluble.
Calcium carbonate (chalk, limestone and marble) is like this. When an acid reacts with a
metal carbonate, the products formed are a salt plus water, but carbon dioxide is also
formed. Here is the general word equation for the reaction:
acid + metal carbonate → a salt + water + carbon dioxide
• You usually observe bubbles of gas being given off during the reaction. You can show that the
gas is carbon dioxide by bubbling it through

11. c1.13 electrolysis
The process of electrolysis
• Positively charged ions move to the
negative electrode during
electrolysis. They receive electrons
and are reduced.
• Negatively charged ions move to the
positive electrode during electrolysis.
They lose electrons and are oxidised.
ELECTROLYSIS OF Hydrochloric Acid
• Produces chlorine at the positive
electrode
• Produces hydrogen at the negative
electrode
Electrolysis
The process in which electrical energy from a d.c. supply decomposes compounds

12. C1.14 the importance of chlorine/Products from
sodium chloride
Learn all of this

13. 1.15 Electrolysis of Water
Water
• Produces oxygen at the positive
electrode
• Produces hydrogen at the
negative electrode
• If the gas relights a glowing
splint, it is oxygen.
Electrolysis of Seawater
• This produces chlorine gas at
the electrode.

14. 1.16 ores
Gold and platinum found naturally in the
environment as they are unreactive.
Most metals are found as ores (usually
reacted with oxygen) in the Earths crust.
Ores are rocks which contain metals.
Extraction = getting the metal out of the
rock. Sometimes you can…
• Heat the rock to get the metal
• Or use electrolysis.
Uses of metals.
Gold= jewellery
Copper = wires
Silver = jewellery
C1.26 Acid rain
Effects of acid rain
- Fish numbers started to decrease.
- Soils are made acid and can harm plants.
- Trees damaged
- Erosion of buildings made of limestone.
Causes of acid rain.
- Dissolved carbon dioxide and acidic gases in
water.
- Sulphur dissolved in water from fossil fuels.
- Burning of fossil fuels which create sulphur.

15. C1.17 Extracting
metal
 anode – The positive electrode used in electrolysis.
 cathode – The negative electrode used in electrolysis.
 electrolysis – The use of an electric current to separate
out the elements in a compound.
 electrolyte – An ionic compound that conducts
electricity when in a liquid state.
 ore – A rock that contains a metal combined with other
elements in concentrations that make it profitable to mine.
Factors which affect how a metal is extracted are
cost and position in the reactivity series
Iron is heated with carbon in a reduction
reaction to extract it from its ore.
Iron oxide + carbon  iron + carbon
dioxide
Aluminium is extracted from its ore by
electrolysis because it is more reactive.
Aluminium oxide  aluminium + oxygen

16. C1.18 Oxidation and reduction
Keywords
Reduction – occurs when oxygen is removed from a compound
Corrosion – when a metal is converted to its oxide by the action of moist air
Oxidation – occurs when oxygen is added to an element or compound
Rusting – the corrosion of iron
Metal extraction is reduction
• Most metal ores are ‘oxides’
• To get the metal we must remove the oxygen
• We say the compound has been reduced. It is a REDUCTION reaction
• Example 1 = Iron oxide is heated with Carbon
Iron oxide + Carbon Iron + Carbon dioxide
• Example 2 = Aluminium is obtained by electrolysis of aluminium oxide
Aluminium oxide Aluminium + Oxygen
Corrosion of metals is oxidation
• Most metals corrode
• Surface of a metal reacts with oxygen (or sometimes water)
• This is called OXIDATION reaction
• More reactive metals corrode more rapidly (less reactive may not corrode at all e.g. Gold)
• A layer of metal oxide forms (this can stop further corrosion e.g. on Aluminium = and Al2O3 layer forms)

17. C1.19 Recycling metals
Keywords
• Recycled metal – when a used metal is melted down and made
into something new.
Many metals can be recycled…
Advantages
• Natural reserves will last longer
• Most use less energy to recycle that to extract. E.g. Aluminium recycling 95% more energy
efficient compared to extraction.
• Reduced mining which damages landscapes and causes pollution (dust and noise)
• Recycling produces less pollution. Examples supporting this are
• Lead from its ore ‘galena’ produces sulfur dioxide
• Carbon dioxide is produced during extraction by electrolysis.
Disadvantages
• Costs money and uses energy to collect, sort and transport metals to be recycled
• This can make it more expensive to recycle some metals the extract them
The most recycled metals in the UK are Lead , Iron and Aluminium and Copper
Method
1. Collecting – requires people to be willing to separate their rubbish
2. Separating different metals
• Iron can be separated using a magnet (quick and easy)
• Others usually separated by hand (time consuming and labour intensive)
3. Purifying – metals are melted down to form blocks

18. Aluminium Copper Gold Iron and Steel
Useful Properties
• Low density
• Does not corrode
(because of layer of
oxide that forms
quickly)
Uses
• Aeroplanes and cars
to make them lighter
(cheaper to run as
they need less fuel)
Useful Properties
• Ductile
• Low reactivity (does
not react with water)
• Good electrical
conductor
Uses
• Electrical cables
• Water pipes
Useful Properties
• Very unreactive
• Does not corrode
• Malleable
• Remains shiny
• Excellent electrical
conductor
Uses
• Jewellery
• Electronic devices
(printed circuit
boards and
connection strips)
Useful Properties
• Cheap to extract by
heating with carbon
• Pure iron too soft but
in alloys is very useful
• Steel (Iron mixed with
carbon and other
metals) is strong and
hard
• Magnetic
Uses (mainly as steel)
• Bridges, cars, cutlery,
electrical goods,
machinery, building
frames, magnetic
products
C1.20 Properties of metals
Keywords
Malleable – can be hammered into shape
Conduct – allows heat or electricity to pass through it
Ductile – can be stretched into wires
Density – the mass of a substance per unit volume; the unit is usually g/cm3
Properties include:– shiny when polished;
conduct heat and electricity; malleable; ductile.

19. C1.21 Alloys
Keywords
Alloy – a metal mixed with small amounts of other metals to improve their properties
Carats – a measure of the purity of gold with pure gold being 24 carats
Fineness – another measure of purity of gold (parts per thousand)
Smart material – a material that’s properties change with a change in conditions
Shape Memory Alloy – an alloy that can return to its original shape when heated
Pure metal
1. All atoms are the same size and therefore closely packed
together.
2. This means that layers of atoms slide over each other which
makes the metal soft.
3. In an alloy different atoms are added which prevent the atoms
sliding so easily = harder and stronger
Examples of Alloys
Alloy steels – iron mixed with other metals
• Stronger that Iron
• Some resist corrosion. Stainless steel NEVER corrodes (Iron with Chromium and Nickel)
Gold - Pure gold (24 carat) too soft. 24 carat gold has a fineness of 1000 parts per thousand
• Copper and silver added to make it harder
Nitinol – Smart material made from nickel and titanium
• Return to original shape when heated.
• Used in repair of arteries (inserted in squashed and cold and warms with body to reshape)
• Flexible glasses frames
Pure metal

20. C1.22 Crude Oil
Key words
• Hydrocarbons are compounds that contain
carbon and hydrogen only.
• Crude oil is a complex mixture of
hydrocarbons

21. C1.23 Crude Oil Fractions
• Crude oil is separated into simpler, more
useful mixtures by fractional distillation.

22. C1.23 Crude Oil Fractions
Fraction Uses
Gases Domestic heating and cooking
Petrol Car fuel
Kerosene Aircraft fuel
Diesel oil Fuel for some cars and trains
Fuel oil Fuel for ships and some power stations
Bitumen Surfacing roads and roofs
There are 6 fractions you need to know…

23. C1.23 Crude Oil Fractions
Fraction Length of
molecule
Ease of
ignition
Boiling point Viscosity
Gases Short
Long
Easy
Difficult
Low
High
Runny
Thick and
sticky
Petrol
Kerosene
Diesel oil
Fuel oil
Bitumen
Key words:
Ignition – to set alight
Viscosity – How thick or runny a substance is
How do the fractions differ?

24. C1.24 Combustion
Key words:
Combustion – a chemical reaction with oxygen (oxidation) to
release energy.
Complete combustion – where all the hydrocarbon is used up.
Oxidation – the addition of oxygen.
+ Energy
released
Any hydrocarbon
Tested for using limewater. CO2
will turn it cloudy if present.

25. C1.25 Incomplete Combustion
Keywords:
• Incomplete combustion – where there is not enough oxygen for the fuel to
completely burn.
• Carbon Monoxide – poisonous gas produced during incomplete combustion.
Water is formed just like in complete combustion but there are not enough oxygen
atoms to form CO2. Soot and Carbon Monoxide are formed instead.
3 different equations show what can happen:
Methane + Oxygen  Carbon (soot) + Water
Methane + Oxygen  Carbon Monoxide + Water
Methane + Oxygen  Carbon Dioxide + Carbon Monoxide + Carbon (soot) + Water
Different percentages of CO2, CO and C are produced depending on the amount of
oxygen present.

26. C1.25 Incomplete Combustion
Problems of incomplete combustion:
• Carbon Monoxide is an odourless, colourless,
toxic gas.
• It reduces the amount of oxygen carried by the
Red Blood Cells.
• Carbon monoxide poisoning can kill.
• Soot can clog pipes carrying waste gases.
• Faulty or blocked boilers can produce carbon
monoxide.

27. C1.26 Acid Rain
Key word:
Acid rain – rain that is more acidic than normal.
Impurities in hydrocarbons such as sulfur react with oxygen to produce
sulfur dioxide. This dissolves in rainwater to form acid rain.
4 Problems of Acid Rain:
• Rivers, lakes and soils become acidic harming living organisms
• Damages trees
• Speeds up weathering of buildings made of limestone or marble
• Corrodes metal

28. C1.27 Climate Change
3 gases trap heat from the Sun and keep the Earth warm – Greenhouse Effect
• Carbon Dioxide
• Methane
• Water vapour
The Earths temperature varies.
Human activity such as burning
fossil fuels may influence this

29. C1.27 Climate Change
• The amount of carbon dioxide in the atmosphere varies
due to human activity – burning fossil fuels.
How to reduce the amount of carbon dioxide in the
atmosphere:
• Iron Seeding Oceans – Adding iron to the ocean encourages
algal growth which photosynthesise and absorb carbon.
They are eaten by other organisms which incorporate
carbon into their shells which sinks to the bottom of the
ocean.
• Converting carbon dioxide back to hydrocarbons – trapping
gases from power stations and reacting them to make
butane or propane to use as fuels.

30. C1.27 Climate Change
Key words:
• Correlation – a pattern which is similar in two variables. It could be due to chance.
• Causation – when one variable causes the effect in the other.
• There is a correlation between carbon dioxide levels in the atmosphere and the
Earths temperature.
• Not all scientists are convinced that increasing carbon dioxide levels cause global
warning.
Because…
• There are fluctuations throughout history
• There are other causes of global warning
• There are other greenhouse gases
• Future predictions are just predictions

31. C1.28 Biofuels
Key words:
Biofuel – A fuel made by humans from animal or plant material that has recently
died.
Ethanol – A fuel made from sugar beet or sugar cane.
Biodiesel – Diesel made from plant material.
Carbon neutral – a fuel that does not add any carbon to the atmosphere overall.
Biofuels are a possible alternative to fossil fuels e.g. ethanol which could reduce
demand for petrol.
Advantages of Biofuels Disadvantages of Biofuels
They are renewable Growing crops for fuels requires land
that could be used to grow food
Plants remove carbon dioxide from the
atmosphere as they grow
Transportation of the fuels produces
carbon dioxide
Burning the fuels produces carbon
dioxide

32. C1.29 Choosing Fuels
4 factors that make a good fuel:
• How easily it burns.
• How much ash or smoke it produces.
• The comparative amount of heat energy it produces.
• How easy it is to store and transport.
• A fuel cell combines hydrogen and oxygen to make water and releases energy.
• Petrol, Kerosene and diesel oil are non-renewable fossil fuels made from crude oil.
• Methane is a non-renewable fossil fuel from natural gas.
Advantages of using hydrogen as a fuel Disadvantages of using hydrogen as a fuel
When hydrogen burns no carbon dioxide is
produced, only water vapour
Hydrogen usually produced from natural gas and
the process releases carbon dioxide
Hydrogen fuel cells are more efficient than petrol
engines
Hydrogen needs to be readily available first
Renewable Petrol stations would have to be converted to
store and sell hydrogen too
Cost of the above

33. C1.31 Alkanes and Alkenes
Alkanes are saturated hydrocarbons which are
present in crude oil.
Learn the
formula
and be
able to
draw each
of these.

34. C1.31 Alkanes and Alkenes
• Alkenes are unsaturated hydrocarbons
Bromine water is used to distinguish between alkanes and alkenes
Ethene + bromine water  colourless
(colourless) (orange)
Ethane + bromine water  orange
(colourless) (orange)
Learn the
formula
and be
able to
draw each
of these.

35. C1.32 Cracking
Cracking involves breaking down long saturated
hydrocarbons (alkanes) into smaller useful ones. Some
of these small molecules are unsaturated (alkenes).
Know how
to crack
paraffin in
the lab.
Why is cracking needed? Crude oil has
different amounts of each fraction. These don’t
always match customer demand so they crack
them to match demand.

36. C1.33 Polymerisation
Many ethane molecules can combine in a
polymerisation reaction.
Learn the formula
and equation

37. C1.33 Polymerisation
4 examples of polymers you need to know…

38. C1.33 Polymerisation
Polymer Properties Use
Poly(ethane) – polythene Flexible, cheap, good
insulator
Plastic bags, plastic bottles,
cling film, insulation for
electrical wires
Poly(propene) –
polypropene
Flexible, shatterproof, high
softening point
Buckets and bowls
Poly(chloroethene) - PVC Tough, cheap, long-lasting,
good insulator
Window frames, gutters,
pipes, insulation for
electrical wires
Poly(tetrafluoroethene)
PTFE or Teflon
Tough, slippery, resistant to
corrosion, good insulator
Non stick coatings for
saucepans, bearings for skis,
containers for corrosive
substances, stain proof
coating for carpets,
insulation for electrical
wires

39. C1.34 Problems with Polymers
3 problems
• Most are not biodegradable.
• They persist in landfill sites.
• They produce toxic gases when burned.
How can we overcome these problems?
• Recycling polymers instead of landfill.
• Development of biodegradable polymers.