Crude oil and hydrocarbons

• Hydrocarbons are compounds that contain hydrogen and carbon atoms only.
• Crude oil is a finite resource that is found in the Earth’s crust- meaning it will run out.
• Crude oil is the remains of organisms that lived and died millions of years ago - mainly plankton which was buried in mud.
• Crude oil is an important source of:

  • fuels such as petrol, diesel, kerosene, heavy fuel oil and liquefied petroleum gases
  • feedstock for the petrochemical industry
• Other useful substances made from compounds found in crude oil include:

  • solvents
  • lubricants
  • detergents
• Alkanes are the simplest form of hydrocarbons.
• Alkanes general formula is CnH2n+2.
• Alkanes are a homologous series.
• A homologous series is a family of hydrocarbons with similar chemical properties who share the same general formula.
• Alkanes are saturated because they only contain singe bonds.
• The first 4 alkanes are methane, ethene, propane, butane.
• Methane-CH4

  This is its displayed formula.

  
• Ethane-C2H6

  This is its displayed formula.

  
• Propane-C3H8

  This is its displayed formula.

  
• Butane-C4H10

  This is its displayed formula.

  
• Viscosity tells us the thickness of a fluid.

  -Fluids with high viscosity flow slowly.

  -Fluids with low viscosity flow faster.
• As the size of the hydrocarbon molecules increases the molecule gets more viscous.

  So very long hydrocarbons flow very slowly and are extremely viscous.
• Flammability tells us how easily a hydrocarbon combusts(burns).
• short chain hydrocarbons are very flammable.

  long chain hydrocarbons aren't as flammable.
• As the size of a hydrocarbon molecules increases, the molecules becomes less flammable
• Long chain hydrocarbons are very difficult to burn.
• Boiling point tells us the temperature at which a liquid turns into a gas.
• Short chain hydrocarbons have low boiling points.

  Long chain hydrocarbons have high boiling points.
• The first 4 alkanes are gases at room temperature.

  This is because they have boiling points which are lower than room temperature.
• As the size of the hydrocarbon molecule increases, the boiling point also increases.
• Very long chain hydrocarbons have very high boiling points.

  Very short chain hydrocarbons have very low boiling points.
• Ships, planes and cars run on hydrocarbon fuel.
• Hydrocarbon fuels release energy when combusted(burned).

  Due to the amount of energy released when they combust they are used as fuels.
• During combustion carbon and hydrogen atoms in the fuel react with oxygen, meaning the carbon and hydrogen are oxidised.
• Complete combustion of a hydrocarbon fuel happens when there is a good supply of air. Carbon and hydrogen atoms in the fuel react with oxygen in an exothermic reaction.
• This is the word equation for complete combustion:

  hydrocarbon + oxygen → carbon dioxide + water
• When balancing complete combustion equations:

  • Start with carbon first.
  • Then hydrogen.
  • Then oxygen.
• Write a balanced equation for the complete combustion of Methane?

  1. CH4 + O2 --> CO2 + H2O
  2. CH4 + O2 --> CO2 + 2H2O
  3. CH4 + 2O2 --> CO2 + 2H2O
• Write a balanced equation for the complete combustion of Ethane?

  1. C2H6 + O2 --> CO2 +H2O
  2. C2H6 + O2 --> 2CO2 +H2O
  3. C2H6 + 3.5O2 --> 2CO2 +3H2O
• Write a balanced equation for the complete combustion of Propane?

  1. C3H8 + O2 --> CO2 +H2O
  2. C3H8 + O2 --> 3CO2 +H2O
  3. C3H8 + 5O2 --> 3CO2 +4H2O
• Write a balanced equation for the complete combustion of Butane?

  1. C4H10 + O2 --> CO2 +H2O
  2. C4H10 + O2 --> 4CO2 +H2O
  3. C4H10 + 6.5O2 --> 4CO2 +5H2O
• Incomplete combustion happens when the supply of air or oxygen is poor. Water is still produced, but carbon monoxide and carbon are produced. Less energy is released than during complete combustion.