elements, mixtures and compounds · web viewfuels are necessary to provide energy for our...

Lesmahagow High School Fuels and Climate Chemistry

Lesmahagow High SchoolS3 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

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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 fromthe earth's crust.

Level 4 Learning OutcomesBy 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).

4. State that coal, oil, gas and peat are fossilfuels and are therefore finite.

5. Describe at least 3 disadvantages of burningfossil fuels in terms of their impact on the

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environment.

6. List at least 4 renewable forms of energy and discuss their advantages and disadvantages.

7. Name some common everyday items which aremanufactured from crude oil.

National 4 Learning OutcomesBy 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 ofthe gases produced from fossil fuels and theirimpact on the Carbon Cycle

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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. Oil rig at sea. The 'Parker Seam' is a seam of coal.

Level 4 Notes

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http://www.google.co.uk/imgres?imgurl=http://www.nationmaster.com/wikimir/images/upload.wikimedia.org/wikipedia/en/thumb/2/2d/Bradford-cllry-diag.jpg/180px-Bradford-cllry-diag.jpg&imgrefurl=http://www.nationmaster.com/encyclopedia/Bradford-Colliery&h=283&w=180&sz=14&tbnid=IjhfoIy535MvsM:&tbnh=93&tbnw=59&prev=/search?q=colliery+diagram&tbm=isch&tbo=u&zoom=1&q=colliery+diagram&usg=__J3pJOV50uag2eBEqFB9nxKvvFy8=&docid=t9XIV4xJjQp_wM&itg=1&hl=en-GB&sa=X&ei=5YX6UL66KamL0AXI74GADQ&ved=0CEgQ9QEwBw&dur=22


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.

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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.

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

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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.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.

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Petroleum Gas


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.

CH4 + O2 H2O + CO2Methane Oxygen Water Carbon

Dioxide

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Iced water to condense out any water produced.

Lime water will turn cloudy with carbon dioxide. Vacuum from

tap water flow.


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.

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. 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

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sun

layer of extra carbon dioxide

Normally the heat energy from the sun is radiated back again into space but the layer of carbon dioxide makes it bounce back down.


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.

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Fuels and Climate Chemistry - Glossary

Word MeaningFuel A substance which burns to release energy.

Combustion Reaction with oxygen (like burning).Exothermic reaction

A reaction which releases heat energy.

Fossil Fuel A fuel formed from dead materials, under intense pressure, over a very long time period.

Finite Limited. Will run out one day.

Renewable Can constantly be replaced.

Biomass Plant or animal material.

Distillation Separation of liquids with different boiling points, by evaporation and then condensation.

Hydrocarbon A compound containing hydrogen and carbon ONLY.

Global warming The heating of the Earth's surface by heat reflected from carbon dioxide and other greenhouse gases.

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