Combustion Reactions

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CombustionReactions
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What is combustion?

• a very rapid reaction of a substance with oxygen
  to produce compounds called oxides.

FUEL OXYGEN ? OXIDE ENERGY
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• commonly referred to as burning
• easily identified by the production of heat
  (exothermic)
• type of synthesis reaction

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Requirements

• Three requirements for a combustion reaction

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Fuels

• Gaseous Fuels
• Natural Gas/Methane - used for cooking, heating
  etc.
• Acetylene - used in welding, cutting etc.

• Liquid Fuels

• Petrol - used for internal combustion engines
  etc.
• Paraffin/kerosene - used in heating appliances
  etc
• Alcohols - used widely but includes
  preservatives, preparations,
  solvents etc.
• Oils - used for lubrication etc.

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Fuels

• Solid Fuels
• Wood/paper/card.
• Plastics - most plastics will release toxic smoke
  during combustion.
• Metals - some metals are flammable, although
  usually very high temperatures are required.
• Foodstuffs - we actually 'burn' our food in order
  to cook it.

The most common fuels are hydrocarbons
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Complete Combustion

• Complete combustion of a hydrocarbon produces
  carbon dioxide gas and water vapour.

Hydrocarbon Oxygen ? Carbon dioxide
Water
methane oxygen ? carbon dioxide water
CH4 2 O2 ? CO2 2 H2O
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Complete Combustion

• Complete combustions occurs when
• Sufficient oxygen is present
• Temperature is hot enough

Complete combustion is characterized by a blue
flame. The flame is hotter than the flame of
incomplete combustion.
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Incomplete Combustion

• If insufficient oxygen is present, hydrocarbons
  burn to produce water vapour along with carbon
  monoxide, carbon dioxide and/or solid carbon.

2CH4 3 O2 ? 2CO 4 H2O
CH4 O2 ? C 2 H2O
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Incomplete Combustion

• Incomplete combustion is characterized by an
  orange or dirty flame.
• Produces black soot and the poisonous gas
  carbon monoxide

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Time to Get to Work

• combustion animation

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