Lesmahagow High School
Fuels and Climate Chemistry
Lesmahagow High School
S3 Chemistry
Fuels and Climate Chemistry
Extraction of useful substances from natural resources.
SCN 3-17b
Materials derived from crude oil and their uses. The importance of
carbon compounds in our lives.
SCN 4-17a
Society's energy needs, the risks and benefits of different energy
sources, including those produced from plants.
SCN 4-04a
Formation and use of fossil fuels, and responsible use and
conservation of finite resources.
SCN 4-04b
The use of fuels and their environmental impact on the carbon cycle.
National 4
Page 1 of 10
Lesmahagow High School
Fuels and Climate Chemistry
Learning Outcomes – Fuels and Climate Chemistry
Circle a face to show how much understanding you have of each
statement:  if you fully understand enough to do what the outcome
says,  if you have some understanding of the statement, and  if
you do not yet understand enough to do what the statement says.
Once you have completed this, you will be able to tell which parts of
the topic that you need to revise, by either looking at your notes
again or by asking for an explanation from your teacher or
classmates.
Level 3 Learning Outcomes
By the end of this topic I will be able to:
1.
Explain how coal, oil and gas are extracted from
the earth's crust.
  
Level 4 Learning Outcomes
By the end of this topic I will be able to:
1.
Describe the formation of coal from decaying
plant material over time and under heat and
pressure.
  
2.
Describe the formation of oil and gas from
decaying sea creatures over time and under
heat and pressure.
  
3.
State that a fuel is a substance which burns
releasing energy (in an EXOTHERMIC reaction).
Page 2 of 10
  
Lesmahagow High School
Fuels and Climate Chemistry
4.
State that coal, oil, gas and peat are fossil
fuels and are therefore finite.
  
5.
Describe at least 3 disadvantages of burning
fossil fuels in terms of their impact on the
environment.
  
6.
List at least 4 renewable forms of energy
and discuss their advantages and disadvantages.
  
7.
Name some common everyday items which are
manufactured from crude oil.
  
National 4 Learning Outcomes
By the end of this topic I will be able to:
1.
Draw a diagram of the Carbon Cycle.
2.
Explain the Greenhouse Effect in terms of
the gases produced from fossil fuels and their
impact on the Carbon Cycle
Page 3 of 10
  
  
Lesmahagow High School
Fuels and Climate Chemistry
Fuels and Climate Chemistry Notes
Level 3 Notes
Extraction of Useful Materials for Fuels
Most of our energy (electrical, gas, heat, light) is produced from
fuels which come from the earth's crust - coal, oil and gas. They
have been used more in recent years as technology has become
available which allows us to get them from the earth's crust more
easily.
Coal is extracted by MINING, either opencast or colliery (deep pit)
mining.
Oil and gas are extracted using OILRIGS or GAS RIGS, as they are
normally found under our oceans, or in areas which were once under
the sea.
Deep pit mine at Bradford.
The 'Parker Seam' is a seam
of coal.
Page 4 of 10
Oil rig at sea.
Lesmahagow High School
Fuels and Climate Chemistry
Level 4 Notes
Formation of Fossil Fuels
Coal, oil, gas and peat are called 'fossil fuels' because they are
formed in the same way as fossils. Coal is formed from the carbon in
ancient trees and plants which, under heat from the earth and
pressure from covering layers of soil etc, reacted over what is
thought to be millions of years, to form carbon in the form of coal.
Coal Formation
Oil and gas were formed similarly, but from the carbon in ancient
animals, which as they decomposed formed the oil and gas which
then became trapped under rock in the sea bed. Oil and gas can rise
through porous rocks but will be stopped by solid layers of rock,
meaning that they will be found at different levels in different
places around the world.
Page 5 of 10
Lesmahagow High School
Fuels and Climate Chemistry
Fuels and their Uses
Fuel: a substance which burns to release energy.
Combustion: the burning of a substance in oxygen (usually from the
air).
An Exothermic reaction is one which gives out heat. All combustion
reactions are exothermic.
Fuels are necessary to provide energy for our everyday needs e.g.
heating, cooking, washing etc., as well as to power luxury items like
our mobile phones and electronic devices. This energy has
traditionally been provided by the burning of fossil fuels in our
homes or in power stations, where they are used to produce
electricity.
Finite sources of energy are sources of energy that, having been
used up, cannot be replaced. All fossil fuels are finite sources of
energy. Over-use of fossil fuels in order to satisfy the energy
demands of the industrial world may lead to a fuel crisis.
Renewable sources of energy can constantly be replaced. Wind
turbines, solar panels, hydroelectric systems, geothermal heating,
tidal power systems, biomass etc., are all renewable sources of
energy.
Biomass is the term given to plant- or animal-based material, i.e.
material from living or recently living organisms (from ‘bio’ meaning
living). Since biomass is produced from a carbon source that can be
replaced, biomass is a renewable source of energy. In the first
instance, biomass can be used as a fuel, e.g. burning logs from dead
trees.
Page 6 of 10
Lesmahagow High School
Fuels and Climate Chemistry
Biomass can also be used produce biofuels. Crops such as sugar-cane
can be grown to produce ethanol, a fuel that can be used in place of
petrol. Biodiesel, another useful fuel, can be produced from waste
vegetable oils and animal fats.
Products from Crude Oil
To be of use, the oil has to be separated into fractions that contain
compounds of roughly the same boiling point. This process is called
fractional distillation.
Although each one is still a mixture of compounds, a fraction can be
used directly as a fuel, or may be used to manufacture other
products.
Much of the crude oil that is used in the UK comes from the North
Sea. However, crude oil also comes from other countries, e.g. in the
Gulf area in the Middle East. The percentage of the different
fractions depends on the source of the crude oil.
Page 7 of 10
Lesmahagow High School
Fuels and Climate Chemistry
Burning Fossil Fuels
Fossil fuels are mainly hydrocarbons with minor impurities. A
hydrocarbon is a compound containing carbon and hydrogen only.
‘Burning fossil fuels’ means that hydrocarbon molecules are reacting
with the oxygen molecules of the air. Natural gas, a fossil fuel, is a
hydrocarbon with the chemical formula CH4.
Natural gas burns in a Bunsen burner. The products of the reaction
are oxides of the elements that make up the hydrocarbon. Energy,
mainly heat, is also given out.
Iced water to
condense out any
water produced.
CH4
Methane
Page 8 of 10
+
O2
Oxygen
Lime water will
turn cloudy with
carbon dioxide.
H2 O
Water
+
Vacuum from tap
water flow.
CO2
Carbon
Dioxide
Lesmahagow High School
Fuels and Climate Chemistry
National 4 Notes
The Carbon Cycle
There are millions and millions of carbon atoms in all living things.
Carbon atoms, joined to atoms of other elements as part of
compounds, are also found in the ground, in the sea and also in the
air (as carbon dioxide).
The carbon atoms do not stay in the same
place … they constantly move round as a
result of various processes, e.g. we put
carbon from glucose molecules in our
bodies into the atmosphere as carbon
dioxide when we breathe out. The
movement of carbon from one place to
another is referred to as the carbon
cycle.
The Greenhouse Effect
Some gases in the atmosphere act like the glass in a greenhouse.
They trap heat, keeping the Earth warm enough for plants and
animals to survive. These gases are called greenhouse gases.
Carbon dioxide is one of the important greenhouse gases.
layer of extra
carbon dioxide
sun
Normally the heat
energy from the sun
is radiated back
again into space but
the layer of carbon
dioxide makes it
bounce back down.
Page 9 of 10
In many industrial areas of the
world, there is significantly more
carbon dioxide being released into
the atmosphere through the
burning of fossil fuels. Some
scientists believe that greatly
increased levels of carbon dioxide
have led to global warming and
changes to climate.
Lesmahagow High School
Fuels and Climate Chemistry
Many of our everyday actions will (directly or indirectly) involve the
production of carbon dioxide from fossil fuels, e.g. travelling to work
by car or bus, using electricity produced by burning fossil fuels. The
carbon we produce in this way (as carbon dioxide) is sometimes
called our carbon footprint. Calculating our carbon footprint can
help us to think about our contribution to global warming and climate
change. Businesses can also calculate the carbon footprint for their
products, e.g. the carbon produced (as carbon dioxide) in the
manufacture of a television or a computer.
Page 10 of 10