Fuels

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Fuels

• Intermediate 2 Chemistry
• Unit 2(a)

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Fuels and combustion

• A fuel is a substance which is burned to release
  energy.
• Combustion is another word for burning.
• Burning requires oxygen (O2).

Enough fuel for 4 billion more years
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Burning fuels

• When a substance burns ALL of the different types
  of atom in it react with oxygen

Atoms in fuel Products
Carbon Carbon dioxide, carbon monoxide
Hydrogen Hydrogen oxide (water)
Sulphur Sulphur dioxide
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Equations

• Write word and chemical equations for the
  following substances burning
• Methane (CH4)
• Glucose (C6H12O6)
• Hydrogen (H2)
• Ethanol (C2H5OH)
• Carbon
• Coal (contains carbon, hydrogen and sulphur)
  no need for a chemical equation here

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Hydrocarbons

• A hydrocarbon is a substance which contains
  hydrogen and carbon ONLY.
• Which of the following substances are
  hydrocarbons?
• Methane (CH4)
• Glucose (C6H12O6)
• Hydrogen (H2)
• Ethanol (C2H6O)
• Carbon

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Testing for the products of combustion
Cobalt chloride paper
Lime water
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Types of combustion

• Look at a Bunsen burner and the different types
  of flame.
• There are 2 types of combustion
• complete and incomplete

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Complete combustion
Incomplete combustion
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Carbon Dioxide vs Monoxide
Chemical Formula Chemical Test Other information
Carbon dioxide CO2 Lime water turns from colourless to cloudy We breath it out it makes drinks fizzy it dissolves in water producing a weak acid it is associated with global warming
Carbon monoxide CO No test Poisonous gas, does not dissolve
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Cars and pollution

• Cars burn petrol (C8H18)
• Petrol sometimes contains sulphur compounds
• What products of combustion will come out of the
  exhaust?

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Sulphur dioxide

• SO2
• Dissolves in rain water to produce acid rain

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Cars and pollution 2

• Nitrogen monoxide and nitrogen dioxide also come
  out the exhausts of cars
• They also cause acid rain
• Where do they come from?

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Nitrogen and Oxygen
N2
O2

• A high-energy spark from the engine spark plug
  allows N2 and O2 to react.
• Oxides of nitrogen (NO, NO2 etc) are produced.

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Alternative Fuels
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