Cracking & Alkenes

• Cracking

  Process by which longer chain hydrocarbons are split into shorter more useful hydrocarbons
• Why are the products of cracking useful

  Shorter hydrocarbons make better fuels

  Shorter alkenes can be used as feedstock for the petrochemical industry to make polymers and detergents
• What type of reaction is cracking an example of

  Thermal decomposition reaction
• Catalyst used in catalytic cracking

  Hot powdered aluminium oxide
• Catalytic cracking

  Long chain alkanes are heated until they vaporise into a gas

  The gaseous alkanes are passed over a hot aluminium oxide catalyst

  This breaks the long chain alkanes into a shorter chain alkanes and alkene
• How is steam cracking different to catalytic cracking

  No catalyst involved
• Alkenes

  Hydrocarbons with a double bond between the two carbon atoms
• What colour change occurs when you add bromine water to alkenes

  Orange to colourless