Chemistry Core Notes Edexcel

1. C1
Proportion of oxygen in the atmosphere
How to test for proportion of oxygen in the atmosphere
To test the percentage of
oxygen in the air you
could use 100cm³of air.
The copper will use the
oxygen in the reaction.
When the reaction is finished there should be about80cm³ of air left. This
means that 20% of the air was oxygen.
The Rock cycle
Sedimentary Rock-
 Formed when layers of sediment built up in lakes and seas.
 The weight of the water squeezes out any water in between the
sediment
 E.g. Limestone and chalk
Metamorphic Rock-
 Formed by the heat and pressureon sedimentary or igneous rocks
 If it doesn’t melt, then it is metamorphic. If it does it will become
magma.
 E.g. Marble

2. Igneous Rock-
 Formed when magma cools down
 If it cools quickly, it is extrusive. This means it will have small crystals
 If it cools slowly, it is intrusive. This means it will have large crystals
 E.g. Granite
Thermal decomposition
How a substancedecomposes when heat is applied. For example:
Calcium carbonate calcium oxide + carbon dioxide
When Carbonates are thermally decomposed, carbon dioxide is formed.
Metal Carbonates formtheir oxide and Carbon dioxide
E.g. Zinc Carbonatecan be heated to formZinc oxide and Carbon dioxide
Neutralisation Reaction
Acid = PH lower than 7
Base = PH higher than 7
Alkali = A basethat is dissolved in water
How can Calcium Hydroxide be produced
When water is added to calcium oxide, Calcium hydroxideis formed.
E.g.
Calcium is an Alkali and can be used to quickly neutralise acidic soil. It can also
be dissolved in water to formlime water.
State Symbols
PH lower than 7 PH Higher than 7

3. Salt formation
Salts are formed through the
neutralisation reaction. However,
different salts are formed from
different acids.
An Acid and a Metal makes a salt
Metal Carbonates
e.g.
HazardSymbols
Metal Oxides and Metal Hydroxides
Metal oxides and Metal hydroxides areoften basses which means it can be
neutralised with acids to forma salt
and water

4. Electrolysis
DC currentapplied to an electrolyte. Positively
charged ions will be attracted to the cathode (-).
Negatively charged ions will be attracted to the anode
(+). This is because oppositecharges attract.
Chlorine
Chlorine can be produced by electrolysing sodiumchloride solution. Chlorine
can be used to treat water supplies. This is because it can kill bacteria and
micro-organisms so thewater is safe to drink. Itis also used in the manufacture
of bleach and PVC.
Bauxite
Bauxite is the main ore for aluminium. The bauxite is melted down to formthe
electrolyte needed for electrolysis. When the currentis applied, the molten
aluminium will sink to the bottom.
Test for chlorine
Chlorine bleaches damp litmus paper white
Test for hydrogen
When a lighted splint is applied, it will make a squeaky pop sound if hydrogen
is present.
Test for oxygen
A glowing split will relight in a test tube of oxygen.

5. Extraction from ore
Where a metal is on the reactivity series
effects how it is extracted. If it is below
carbon, it can be extractred by a reduction
reaction with carbon. This is done by heating
the metal with carbon. Metals more reactive
than carbon are extracted using eloectrolysis.
Metals such as gold are found unombined.
This meand it can be easily removed fromits
ore.
Oxidisation and reduction
In the oxidation and reduction reaction
below. Copper dioxide is reduced. This
means oxygen is removed. Carbon is
therefore oxidised. This means it is gaining
oxygen.
Properties of Metals
Typical properties:
 Strong (but can be bent or hammered into shape)
 Conduct heat
 Conduct electricity
Aluminium:
 Low density
 Corrosion-resistant
 Purealuminium isn’tstrong but can be in alloys

6. Copper:
 Hard
 Strong
 High melting point
 Good conductor of electricity
 Good for water pipes (Below hydrogen in the reactivity series so doesn’t
react with water)
Gold:
 Shiny
 Easy to shape
 Non-reactive
Corrosion of Metals
Metals higher up in the reactivity series are more likely to corrodeas they
react more easily with oxygen
Iron
Iron that is extracted in a blast furnaceis only 96% iron. These impurities make
the iron brittle so it doesn’t havemany uses. When these impurities are
removed, the iron atoms are all the same size. The
layers of iron atoms can then slide over each other.
This means the iron is too bendy for most uses.
Steel
Steel is produced when small amounts of carbon are added to iron to form an
alloy.
Shape memory alloys
These are metal alloys that can go back to its original shape. An example of this
is nitinol. This is made fromnickel and titanium. When heated, it returns back
to its original shape. This can be used in glasses frames or stents for damaged
blood vessels.

7. Hydrocarbons
A hydrocarbon is an atom made up of only hydrogen and carbon. Itcan be
found in crudeoil. Hydrocarbons can beseperated int sizes using fractional
distilation
Fractional Distilation
Fractional Distilation Uses
Complete Combustion
Occurs when there is enough oxygen

8. Incomplete Combustion
Occurs when there is not enough oxygen
Choosing Fuels
When choosing a fuel there are 4 things you need to consider:
 Ease of ignition
 Energy value (amount of energy released)
 How much ash and smokeit leaves behind
 Storageand transport
Problems of Burning Fossil Fuels
When fossilfuels are burnt, carbon dioxide and water vapour are released into
the air. Sulfur impurities are also released into the atmosphere. If there is not
enough oxygen, Itwill not burn properly and will release carbon sootand
carbon monoxide into the atmosphere.
Acid Rain
Acid rain is formed when sulfuric acid from power stations and cars etc. mix
with clouds to form dilute sulfuric acid. This falls as acid rain. Acid rain can
acidify lakes and ponds killing plants and animals that live in it. Itcan also
damage trees, limestone buildings and stone statues.
Sulfur can be removed from fuels before they are burnt. This however, costs
more money and uses more fossilfuels to do so.
Acid gas scrubbers usecalcium carbonateto clean up fumes frompower
stations before it enters the environment.
Cars are now fitted with catalytic converters turn harmful gases into cleaner
gases.
Greenhouse Gases
Greenhousegases such as carbon dioxide, methane and water vapour, actas
an insulating layer that blocks in radiation fromthe sun. This is causing our
planet to heat up (global warming).

9. Reducing Carbon Dioxide Levels
Iron seeding
Iron is needed for photosynthesis. If itis injected into the upper levels of the
sea, then the growth of phytoplankton is promoted. These phytoplankton
remove Carbon dioxide fromthe air through photosynthesis and put out
oxygen.
However, somephytoplankton grow to become toxic. Micro-organisms that
feed on dead plankton useup oxygen. This creates ‘dead zones’ in the sea
wherenothing can live.
Converting Carbon Dioxide to Hydrocarbons
Scientists have been trying to find a way to convertcarbon dioxide back into
hydrocarbons. They havemanaged to convertcarbon dioxide into small chains
of hydrocarbons butmaking long chains needed for petrol is more challenging.
Biofuels
Biogas
Biogas is produced when micro-organisms decomposeanimalwasteor dead
plants. This is becausethey build up carbon dioxide when they are alive, and
when they die, this is released. This biogas can be burnt to produceheat to
turn a turbine or can be used for heating
Advantages Disadvantage
Renewable Less land to grow food
Easy to replace as crops grow quickly Large storagespace
Carbon neutral (No carbon is
released into the atmosphere)
Highly flammable (hard to store)
Clean fuel (there are few pollutants
released)
Cheap

10. Bioethanol
Sugar beet and sugar canecan be fermented with yeastto form ethanol
(alcohol). If you add 90% petrol to it, you create Gasohol. Cars can run from
this.
Advantages Disadvantage
Less crude oil is required Less land to grow food
Carbon neutral (Doesn’trelease
carbon dioxide)
Requires suitable climate to grow the
sugar beet and sugar cane
Clean fuel (Few pollutants) Distillation is needed after
fermentation. This uses electricity
Pollutants include carbon dioxide and
water vapour. Theseare greenhouse
gases.
Hydrogen fuel cell
Like a battery, it can produce energy. Ittakes in hydrogen and oxygen and
creates water and energy.
Advantage Disadvantage
No pollutants Gases require large storage space
No recharging required Flammable (Hard to store)
More than 80% efficient Hydrogen still needs to be obtained
through electrolysis.
Less energy lost through heat and
friction
Measuring energy content in fuels
1. Measurefuel mass before
2. Measureout volume of water into a beaker
3. Add a draftshield to preventthe flame frombeing blown away fromthe
water
4. Measuretemperature of the water
5. Light the fuel until the water rises 10 degrees
6. Then blow out the flame and re-measurethe fuel.
7. Calculate the difference
8. Repeat with another fuel
The fuel that has used the least fuel is the bestfuel.

11. Cracking
Heat and a catalyst are applied to long chains of hydrocarbons. This causes
them to break into smaller chains. This process is usefulas long chains of
hydrocarbons havelimited uses.
1. Heat is applied to the alkane and
the catalyst
2. As the alkane passes over the
catalyst, it will crack into smaller
hydrocarbons.
3. These smaller hydrocarbons go
down the delivery tube and into the jar.
When you heat the boiling tube, it expands. If you kill the heat, the glass
will shrink back to its original size. This creates a vacuumwhich sucks in the
cold water. When the cold water comes into contact with the hot glass, the
glass will shatter.
Polymerisation
Polymers aremade up of repeated links called monomers. Pressureand a
catalyst are applied to alkenes. This breaks open the double bond, allowing it
to join other monomers. When ethene is turned into a polymer, poly (ethene)
is produced.
Chemical Formula
Monomers Polymers

12. Uses of synthetic polymers
Problems with plastics
Solutions

13. Alkanes and Alkenes
Alkanes are saturated and doesn’tchange the colour of bromine water.
Alkenes areunsaturated and decolourises bromine water.
Drawing alkanes
1. Draw the carbons
2. Draw the bonds. Alkanes haveone double bond.
3. Carbons can only have 4 bonds. Count how many they have already used
up and add more so it has a total of 4 bonds

14. 4. Then add the Hydrogens
Cracking
Thermal decomposition reaction. This can break
down long chains of hydrocarbons into smaller
more usefulhydrocarbons. This can be done by
the useof heat and a catalyst.
1. Heat the alkane and catalystat the same
time.
2. As the alkane starts to condense, it will pass over the catalyst. This
causes it to crack into alkenes.
3. The alkenes will then pass the through the delivery tube and up into the
beaker.
4. The water will be pushed out of the beaker and you will be left with
alkenes.
5. You can then test it with bromine water. Itshould decolourise. This
proves that it is an alkene not an alkane.
Polymerisation
Polymers arelong chains of repeated monomers. Thesecan be created by the
use of pressureand a catalyst. An example of this is the monomer glucose
forming the polymer starch.

15. The polymer, polyethene can be created when the double bond in the
monomer, ethene breaks open and allows many other monomers to join.
Polymer properties anduses toremember-