Oils, Earth and Atmosphere

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Oils, Earth and Atmosphere
(AQA)
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Crude oil Revision
Crude oil is a mixture of HYDROCARBONS (compounds
made up of carbon and hydrogen). Some examples

• Longer chains mean
• Less ability to flow
• Less flammable
• Less volatile
• Higher boiling point

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Using Crude Oil
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Using Crude Oil
Benefits
Drawbacks
Cheap to extract
Plastics dont biodegrade
Crude Oil
Wide range of uses as fuel
Burning fossil fuels causes pollution
Used to make plastics
Disposal of materials uses up land fill sites
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Ethanol
Ethanol is an important chemical. Many countries
are increasing the amount of ethanol put into
their petrol supplies
Ethanol is a clean burning energy source and
produces little or no greenhouse gases. How is
it made?
The fossil fuel way
Ethene is produced by cracking oil
The renewable way
Sugar is produced from standard crops like sugar
cane and corn
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Cracking
Shorter chain hydrocarbons are in greater demand
because they burn easier. They can be made from
long chain hydrocarbons by cracking
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Cracking
This is a THERMAL DECOMPOSITION reaction, with
clay used as a catalyst
Cracking is used to produce plastics such as
polymers and polyethanes. The waste products
from this reaction include carbon dioxide,
sulphur dioxide and water vapour. There are
three main environmental problems here

• Carbon dioxide causes the _________ effect
• Sulphur dioxide causes _____ _____
• Plastics are not _____________

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Alkenes
Alkenes are different to alkanes they contain
DOUBLE COVALENT bonds. For example
This double bond means that alkenes have the
potential to join with other molecules this
make them REACTIVE. They have the general
formula CnH2n
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Monomers and Polymers
Heres ethene again. Ethene is called a MONOMER
because it is just one small molecule. We can
use ethene to make plastics
Step 1 Break the double bond
Step 2 Add the molecules together
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Another way of drawing it
Instead of circles, lets use letters
General formula for addition polymerisation
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Some examples
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Uses of addition polymers
Poly(ethene)
Poly(propene)
Poly(chloroethene), PVC
Poly(styrene)
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Disposal of plastics
Words recycling, greenhouse, decompose,
biodegradable, poisonous
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Vegetable Oils
When plants photosynthesise they produce glucose.
They can also produce vegetable oils and we can
use these for food and fuel
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Extracting Oil
Step 2 Remove oil by pressing
Step 1 Crush the plant
OR step 3 Remove oil by distillation
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Healthy and Unhealthy Oils
Unhealthy oils
Saturated
Healthy oils
Unsaturated
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Saturated vs. Unsaturated Fats
Some oils are more healthy than others. Fish
oils contain the nutrients Omega-3 and Omega-6.
These oils are unsaturated like ethene
Testing for double bonds
Clearly, it is important for scientists to be
able to test if a food contains healthy
unsaturated fats or unhealthy saturated fats.
Heres how its done
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Turning unsaturates into saturates
600C, Nickel catalyst
The unsaturated fat is hardened by
hydrogenation. Hydrogenated oils have a higher
melting point and so are solid at room
temperature.
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Artificial Additives
Why do we use additives?
Some examples
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E numbers
If artificial additives are approved they are
given an E number
E100E199 (colours) E200E299 (preservatives)
E300E399 (antioxidants, acidity regulators)
E400E499 (thickeners, stabilizers, emulsifiers)
E500E599 (acidity regulators, anti-caking
agents) E600E699 (flavour enhancers) E900E999
(miscellaneous) E1000E1999 (additional
chemicals)
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Emulsions
Whats an emulsion?
Its a mixture of oil and water, like in salad
dressing
Paint is an emulsion. Other examples
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Why use emulsions?
Emulsions can have varying textures and this
makes them useful. Some examples
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Chromatography
Chromatography can be used to separate a mixture
of different inks. Some example questions
1) Ink X contains two different colours. What
are they?
2) Which ink is ink Z made out of?
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Chromatography
Chromatography can be used to test which foods
contain which ingredients. For example, consider
the dye Sudan 1, which was found in 450 foods in
2005
Sudan 1
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The Structure of the Earth
The average density of the Earth is much higher
than the crust, so the inner core must be very
dense
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Movement of the Lithosphere
The Earths LITHOSPHERE (i.e. the _______) is
split up into different sections called ________
plates
Words radioactive, crust, convection, tectonic,
year
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Forming new crust
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Continental Drift
Look at the coastlines of South America and
Africa. I wonder of they used to fit together
Alfred Wegener
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Tectonic theory
People once thought that the oceans and the
continents were formed by shrinkage from when the
Earth cooled down after being formed. Alfred
Wegener proposed something different. People
didnt believe him because he couldnt prove it,
so he had to find some evidence
These continents look like they fit together.
They also have similar rock patterns and fossil
records. These are the two pieces of evidence
that led me to believe that there was once a
single land mass. This is my TECTONIC THEORY.
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Forming mountains
The formation of mountain ranges can be explained
by tectonic theory. Consider the Himalayas at
the top of India
The intense heat and pressure from this process
causes the rocks to change structure into
metamorphic rocks.
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Tectonic theory

• The Evidence
• Some continents look like they used to fit
  together
• Similar rock patterns and fossil records

The Problems Wegener couldn't explain how
continental drift happened so nobody believed him

• The Answer
• Scientists discovered 50 years later that the
  Earth generates massive amounts of heat through
  radioactive decay in the core. This heat
  generated convection currents in the mantle
  causing the crust to move
• We also now know that the sea floor is spreading
  outwards from plate boundaries

Conclusion scientists now believe Wegeners
Tectonic Theory
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Evolution of the Earths Atmosphere
Present day atmosphere contains 78 nitrogen, 21
oxygen, 1 noble gases and about 0.03 CO2
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Group 0 The Noble gases
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Group 0 The Noble gases
Some facts about the noble gases

• They include neon, argon and ___________
• They are all very ________

3) Helium is less _____ than air and is used in
balloons and airships (as well as for talking in
a silly voice)
4) Argon is used in light bulbs (because it is
so unreactive) and argon , krypton and ____ are
used in fancy lights
Words neon, dense, unreactive, helium
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Evolution of the Earths Atmosphere
Some of the oxygen is converted into ozone. The
ozone layer blocks out harmful ultra-violet rays
which allows for the development of new life.
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Carbon dioxide in the atmosphere
The amount of CO2 in the atmosphere is affected
by 3 things
1) Geological activity moves carbonate rocks
deep into the Earth and they release ______
_______ into the atmosphere during volcanic
activity.
2) When fossil fuels are burned the carbon
contained in them reacts with _____ to form CO2.
3) Increased CO2 in the atmosphere causes a
reaction between it and _______. These reactions
produce two things INSOLUBLE CARBONATES (which
are deposited as ______) and SOLUBLE
HYDROGENCARBONATES (which ________ in the
seawater). These reactions do not remove ALL of
the new CO2 so the greenhouse effect is still
getting _______!
Words oxygen, seawater, carbon dioxide, worse,
dissolve, sediment