C9- crude oil and fuels

• What are crude oils useful for

  Plastics, cosmetics, medicines and fuels
• What is crude oil

  A finite oil made of dead parts of plankton and plant biomass that were burried in the mud millions of years ago
• How is crude oil formed and extracted

  Overtime the mud became rock which heated and pressurised the remains

  it did not decay or rot it changed chemically into crude oil

  is extracted by drilling underground
• What is plankton

  Tiny animals
• What is a hydrocarbon

  A compound made only of hydrogen and carbon atoms
• What are alkanes

  Saturated hydrocarbons That only have single bonds between the carbon atoms
• What does saturated mean

  Has as many hydrogen atoms as possible without a double bond
• What is the homologous series

  they have similar chemical properties and have a general formula of $c^n$$h^{2n+2}$
• What are the 4 main alkanes


  CH4- methane

  C2H6- ethane

  C3H6- propane

  C4H10- butane
• What pattern links the size of a hydrocarbon and how it behaves

  As the number of carbon atoms in the hydrocarbon increases the size of the molecule increases

  
  

  this means that there are more intermolecular forces of attraction between the hydrocarbon molecules
• What happens when more energy is needed to overcome the intermolecular forces of attraction between hydrocarbon molecules

  • boiling point increases
  • Viscosity increases
  • Volatility decreases (how easy it becomes a gas)
  • Flammability decreases
• Why are Hydrocarbons with large number of carbon atoms not suitable as fuels for vehicles

  Do not flow easily through pipes as are either solid at room temp or have a high viscosity

  They do not vaporise easily in engines and furnaces

  Are difficult to ignite
• What is a fraction

  A mixture of hydrocarbons that have similar boiling points

  Fractions have similar chain lengths
• What different parts is crude oil made off

  Petrol, kerosene, diesel
• How is crude oil separated

  fractional distillation
• Process of fractional distillation

  1. the crude oil is heated
  2. Most parts of the crude oil evaporate into gas
  3. The gasses move up the column
  4. It is extremely hot at the bottom of the column
  5. It cools down at the top of the column
  6. As the gasses rise they get cooler
  7. The fractions condense when the temp reaches the boiling point and the gasses change state into a liquid
  8. The fractions are collected out of a pipe
• Where do short chain hydrocarbons come off the column

  Short chain - the top

  Long chain- the bottom
• Short chain hydrocarbon features

  1. low boiling point
  2. High volatility
  3. Runny (low viscosity)
  4. High flammability
• Long chain hydrocarbon features

  1. High boiling point
  2. Low volatility
  3. Thick (high viscosity)
  4. Lower flammability
• What are the short and long chain hydrocarbon

  Short - c3 to c10

  Long - c20 to c40
• When is complete combustion

  When their is a plentiful supply of air
• What is the equation for complete combustion

  Hydrocarbon + oxygen = co2 + water
• when is incomplete combustion

  If the supply of oxygen is limited
• incomplete combustion equation

  Hydrocarbon + oxygen = carbon monoxide + water
• why is carbon monoxide poisonous

  it combines with haemoglobin in red blood cells preventing them from carrying oxygen
• What is an alkene

  A hydrocarbon with one carbon double bond (C=C)

  Formula $c^n$$H^{2n}$
• What does unsaturated mean

  Having carbon-carbon double bonds

  Contains The greatest possible number of hydrogen atoms
• What is cracking

  1. crude oil is heated to a vapour then either
  2. Mixed with steam and heated
  3. Or gets passed over a hot catalyst
  4. Thermal decomposition takes place and the molecules crack
• What type of reaction is cracking

  Thermal decomposition when long chain hydrocarbons break down into short chains
• What is the avagardo constant

  $6.02\times10^{23}$
• How to find the mass of a substance using molar ration

  1. write the balanced symbol equation for the reaction
  2. Identify the known and the unknown
  3. Identity the molar ratio
  4. Calculate the relative mass of the known (add atomic masses, carbons is 12)
  5. Calculate the moles of the known mass/mr
  6. Using molar ratio calculate the moles of the substance your calculating
  7. Calculate the Mr of the unknown
  8. Calculate the mass of the substance using the equation mass = moles x Mr
• Number of moles equation

  mass/relative atomic mass