(7) Organic Chemistry

• Hydrocarbons are chains or rings
• Crude oil is a finite resource
• Crude oil is a sticky black liquid
• Crude oil is a mixture of compounds that are mainly hydrocarbons
• Alkanes have no double bond
• Alkanes are colourless
• What is the general formula for alkanes?

  CnH2n+2
• Alkanes react with halogens and in combustion
• Alkanes can undergo cracking
• Alkanes are generally unreactive
• Alkanes are saturated
• Methane has one carbon
• Ethane has two carbons
• Propane has three carbons
• Butane has four carbons
• Low boiling point to high, name each fraction product

  Refinery gas

  Gasoline

  Kerosene

  Diesel

  Fuel oil

  Bitumen
• high boiling point means low..

  viscosity
• high boiling point means not very vola...

  volatile
• different hydrocarbons have different boiling points
• smaller hydrocarbon molecules mean weaker intermolecular forces
• what is viscosity

  how easily something flows
• what is fractional distillation?

  separating crude oil into simpler more useful mixtures
• which end is cooler in fractional distillation?

  the top end
• fractions have similar..

  hydrogen and carbon atom numbers

  boiling points

  ease of ignition

  viscosity
• what are the products of complete combustion?

  CO2 and H2O
• What needs to be in good supply for complete combustion to occur?

  Oxygen
• Give reaction for combustion of a hydrocarbon

  hydrocarbon+O2->CO2+H2O
• give products of incomplete combustion

  H2O, CO and C
• What type of combustion releases more energy?

  Complete
• Why does incomplete combustion occur?

  poor O2 supply
• What temperatures are needed for catalytic cracking?

  470-550
• what catalyst is used for catalytic cracking?

  aluminium oxide
• Describe catalytic cracking

  hydrocarbon turned into vapour

  passed over catalyst which is in powder form

  when hydrocarbon contacts catalyst covalent bonds are broken due to thermal decomposition

  hence it can break into smaller molecules
• what needs higher temps, catalytic or steam/thermal?

  steam/thermal
• In thermal/steam cracking you get more ring structures and more alkenes
• No catalyst needed in steam cracking just steam
• Give three characteristics of carbon monoxide

  toxic

  odourless

  colourless
• What is carbon on its own also known as?

  Soot
• What medical condition makes it hard to breathe if you come into contact with soot?

  Asthma
• Alkenes are unsaturated