Crude oil + fuels

• What are the remains of living sea creatures that crude oil is made from?

  Plankton decayed in mud
• What kind of resource is crude oil, in terms of its availability?

  Finite
• What is crude oil made of?

  A mixture of hydrocarbons
• Why are larger molecules from fractional distillation less useful?

  They are less useful as fuels
• What two elements are hydrocarbons made of?

  Hydrogen and carbon
• What happens to the larger molecules from fractional distillation?

  They are broken down into smaller molecules
• What is the purpose of cracking?

  To break larger alkanes into smaller ones
• What products are formed during cracking?

  Smaller alkanes and at least one alkene
• Why must crude oil be separated before it can be useful?

  Because it is not of much use alone
• Into what are the different substances that crude oil is separated into called?

  Fractions

  
• What property of hydrocarbons allows them to be separated by fractional distillation?

  Different boiling points

  
• What are the steps of fractional distillation?

  • Heat the crude oil to evaporate it.
  • The hot gases rise up the fractionating column.
  • The higher up the column the cooler it gets.
  • The different fractions condense and are collected.
• What products are formed during complete combustion of hydrocarbons?

  Carbon dioxide and water
• What type of bond do alkenes have?

  At least one carbon-carbon double bond
• Why are alkenes described as unsaturated?

  Because they have at least one double bond
• What happens when bromine water is added to an alkene?

  It turns colourless
• Why does bromine water stay orange when added to alkanes?

  Alkanes are less reactive than alkenes
• What are alkenes used to make?

  Polymers
• What type of reaction is cracking?

  Thermal decomposition
• What are the two ways cracking can be done?

  • Steam cracking - uses steam at very high temperature
  • Catalytic cracking - uses a catalyst and high temperature
• What temperature is used in steam cracking?

  About 850°C
• What temperature is used in catalytic cracking?

  About 550°C
• What is the catalyst used in catalytic cracking?

  Zeolite
• Why are alkanes described as saturated hydrocarbons?

  They contain the maximum number of hydrogen atoms
• What type of bonds are between the carbon atoms in alkanes?

  Single covalent bonds
• What primarily determines the boiling point of a hydrocarbon?

  Strength of intermolecular forces
• How does the size of a molecule affect its intermolecular forces and boiling point?

  Larger molecules have stronger forces and higher boiling points
• What happens when the smaller fractions from crude oil are burned?

  They transfer lots of heat energy
• What term describes reactions that transfer heat energy to the surroundings?

  Exothermic
• What are the two types of combustion?

  • Complete combustion - fuel reacts with plentiful oxygen
  • Incomplete combustion - fuel reacts with insufficient oxygen
• What two products are produced during incomplete combustion of hydrocarbons?

  Water and either carbon monoxide or carbon
• Why is incomplete combustion less efficient than complete combustion?

  Releases less energy usefully as heat
• Why is carbon monoxide (CO) a dangerous chemical?

  It prevents oxygen from being carried in your body
• What does carbon monoxide do to red blood cells?

  Binds to the haemoglobin
• How is carbon monoxide detected?

  Using alarms
• What are the first four alkanes?

  • Methane
  • Ethane
  • Propane
  • Butane