organic chem

• distillation is used to separate mixtures which contain a liquid .
• fractional distillation is the process whereby a mixture of liquids with different boiling points are separated by heating them until they vaporise.
• combustion is a chemical reaction where a substance reacts rapidly with oxygen and gives of heat to release energy

  The three types of combustion are rapid, explosive and spontaneous
• explosive combustion occurs when there is not enough oxygen present so that the fuel does not have time to react completely , this results in a sudden explosion
• spontaneous combustion occurs when a material heats up due to its own internal friction (eg coal) and reaches a temperature at which it ignites without any external source of heat being applied
• rapid combustion occurs when a large amount of fuel burns quickly but steadily
• the general equation for combustion is : Fuel + Oxygen -> Carbon dioxide + Water
• a hydrocarbon is an organic compound made from only carbon and hydrogen atoms
• alkenes are hydrocarbons which only contain carbon and hydrogen atoms.
• crude oil is a finite resource that is found in the earths crust.

  it is the remains of organisms.

  Fractional distillation is used to separate them
• small hydrocarbon molecules have weak intermolecular forces
• incomplete combustion happens when there is a poor supply of oxygen

  
  

  Complete combustion happens when there is plenty of oxygen. it releases a lot of energy.

  the only waste products are carbon dioxide and water vapour
• The cracking of crude oil happens by a reaction in which larger saturated hydrocarbons are broken down into smaller unsaturated hydrocarbons
• alkanes have all c-c single bonds and are saturated

  The first four alkanes are methane, ethane, propane and butane
• as the length of a hydrocarbon changes the properties change.

  The shorter the carbon chain, the more flammable they become
• cracking is a thermal decomposition because the bonds are broken by heating and the products are gases