alkenes and alkanes

• general formula of alkanes

  CnH2n+2
• what are the first four alkanes?

  methane

  ethane

  propane

  butane
• what is the general formula for alkenes?

  CnH2n
• what are the first four alkenes?

  ethene

  propene

  butene

  pentane
• what does incomplete combustion happen instead of complete combustion?

  when there is not enough oxygen present
• identify 2 harmful products of incomplete combustion

  carbon(soot)

  carbon monoxide
• 2 methods for cracking long chain alkanes into short chain alkanes and alkenes?

  1)vapourise alkane at a higher temperature and pass over a catalyst

  2)vapourisw alkane at high pressure and high temperature and react with steam
• what does unsaturated mean?

  a compound that contains double carbon bonds
• what is crude oil?

  a mixture of hydrocarbons(mainly alkanes)

  formed from plankton from millions of years ago
• crude oil is separated into different fractions using?


  fractional distillation
• what is meant by the term fraction?

  a group of similar length chain hydrocarbons
• how does fractional distillation work?(using crude oil)

  1)crude oil is heated

  2)most fractions evaporate and rise up at the column

  3)each fractions cools and condenses at different temperatures in the column

  4)this is because hydrocarbons have different boiling point

  HER CRAZY COUSIN BITES PEOPLE
• what happens to the viscosity as you move down the fractional distillation column?

  increases
• what happens to the boiling point as you move down the fractional distillation column?

  increases
• what happens to the flammability as you move down the fractional distillation column?

  decreases
• what happens to the chain length as you move down the fractional distillation column?

  increases
• what colour change would you observe when bromine reacts with alkenes?

  orange to colourless