Alkanes

• General formula for Alkanes

  CnH2n+2
• Describe the polarity of alkanes

  • Non-polar
  • as the electronegativity of carbon and hydrogen are very similar
  • They only have weak Van der Waals forces
• What happens to boiling points of alkanes as the size increases?

  As the alkanes chain length increases the boiling point increases
• What state are shorter alkanes usually in?

  Gas at room temperature
• Which have a lower melting point branched or straight chained alkanes?

  • Branched alkanes.
  • Because they cannot pack together as closely as straight chained alkanes
  • Van der Waals forces are weaker
• Are alkanes soluble or insoluble in water?

  Insoluble

  • Because water molecules are held together by hydrogen bonds which are stronger than Van der Waals forces between alkane molecules
• Describe the reactivity of alkanes

  • Relatively unreactive
  • They have strong carbon-carbon and carbon-hydrogen bonds
• What don't alkanes react with?

  Do not react with acids bases oxidising agents and reducing agents
• What do alkanes react with?

  Halogens

  if:

  • They burn in plentiful supply of oxygen to form carbon dioxide and water
  • Or in restricted supply of oxygen to produce carbon monoxide and carbon