1. Fossil Fuels
C2.5
Hydrocarbons

2. Starter Define the following three terms: Fossil Fuel
Non-renewable resource
Greenhouse gas

3. Starter
A Fossil Fuel is a fuel that is derived from organisms that lived long ago
A Non-Renewable Resource is a resource that cannot be reformed in a reasonable timescale
A Greenhouse Gas is a gas that causes an increase in the overall temperature of the Earth

4. Using Fossil Fuels
Much of the worlds energy needs are met by burning fossil fuels. There are a number of advantages and disadvantages however, of using these fuels in this way.

5. Advantages of fossil fuels
Reliabilty
Unlike, for example, wind or sunshine (especially in Wales!), fossil fuels are available all year round, 24/7
Variety
Fossil fuels are available in a number of different forms. This means we can match the fuel with its use. Petrol, for example can be separated and properties matched to the exact use it is intended for.

6. Disadvantages of fossil fuels
Non Renewable
Because fossil fuels take so long to form, they are classed as non-renewable. Resources of fossil fuels are being used much quicker than they can be replaced.
Production of Carbon Dioxide
Combusting fossil fuels produces carbon dioxide which is a greenhouse gas.
It absorbs infrared radiation from the Earth’s surface and emits some of it back, therefore raising the surface temperature. This causes climate change leading to serious environmental consequences.

7. Disadvantages of Fossil Fuels

8. Disadvantages of Fossil Fuels
Acid Rain
Many fossil fuels contain impurities of sulfur and upon combustion, this is turned into sulfur dioxide. This reacts with water to make sulfuric(IV) (sulfurous) acid.
H2O(l) + SO2(g)  H2SO3(aq)
This is then oxidised to make sulfuric (VI) acid
H2SO3(aq) + ½ O2(g)  H2SO4(aq)
Nitrogen and oxygen react at the high temperatures inside combustion engines to make oxides of nitrogen which react with water to form nitric acid HNO3
Acid rain can cause serious damage to vegetation, wildlife and buildings

9. Disadvantages of fossil fuels

10. Disadvantages of fossil fuels
Carbon Monoxide Formation
If there is a shortage of oxygen, incomplete combustion of fossil fuels occurs resulting in the production of carbon monoxide.
CH4(g) + 1½O2(g)  CO(g) + 2H2O(g)
Carbon monoxide is toxic as it binds to haemoglobin in the blood, ‘blocking’ the binding of oxygen.
Incomplete combustion also reduces the efficiency of a fuel.

11. CaCO3(s) + ___HNO3(aq)  _____ + _____ + _____
Knowledge Check
Name two other greenhouse gases (aside form carbon dioxide) that contribute to global warming.
Complete the equation to show what happens when acid rain runs over a marble statue:
CaCO3(s) + ___HNO3(aq)  _____ + _____ + _____
Why do cars that are incorrectly adjusted give out black smoke from their exhaust pipes?
Write an equation to show the formation of carbon monoxide from the combustion of butane.

12. Answers Methane and water vapour
CaCOs(s) + 2HNO3(aq)  Ca(NO3)2(aq) + CO2(g) H2O(l)
The smoke indicates carbon is present – indicating incomplete combustion of the fuel
C4H10 + 4½O2  4CO + 5H2O