organic chem

• Where is crude oil found?

  In rocks
• What is crude oil formed from?

  The remains of an ancient biomass consisting mainly of plankton that was buried in mud
• What chemically is crude oil?

  A mixture of a large number of compounds; mainly hydrocarbons
• What is a hydrocarbon?

  A molecule made up of carbon and hydrogen only
• What type of hydrocarbons are most of those found in crude oil?

  Alkanes
• What is the general formula of alkanes?

  CnH2n + 2
• What are the first four members of the homologous series of alkanes called?

  Methane, ethane, propane and butane
• What is a homologous series?

  A family of organic compounds that have the same functional group, similar chemical properties and the same general formula
• How can you separate crude oil into fractions?

  By fractional distillation
• What does each fraction of crude oil contain?

  Molecules with a similar number of carbon atoms
• What can we use each fraction of crude oil for?

  As fuels or feedstocks for the petrochemical industry
• Name five fuels produced from crude oil

  Petrol, diesel, kerosene, heavy fuel oil and liquified petroleum gases
• Name four useful materials produced by the petrochemical industry from crude oil fractions

  Solvents, lubricants, polymers and detergents
• Why are there such a vast range of natural and synthetic carbon compounds?

  Because of carbon atoms' ability to form families of compounds
• Describe the four steps involved in fractional distillation

  Crude oil is heated to evaporate it and turn it into a vapour, the vapour rises through the column and cools, the vapours condense when they are cool enough, and liquids are removed from the column at different heights
• What three properties of hydrocarbon change as the size of the molecule increase?


  Boiling point, viscosity and flammability
• How does the boiling point of a hydrocarbon change as its size increases?

  It increases
• How does the viscosity of a hydrocarbon change as its size increases?

  It increases
• How does the flammability of a hydrocarbon change as its size increases?

  It decreases
• Why are hydrocarbons good fuels?

  Because during their combustion they release energy
• What happens to the carbon and hydrogen in a hydrocarbon during combustion?

  They are oxidised
• What are the products of complete combustion of a hydrocarbon?

  Carbon dioxide and water
• What is the name of the process where hydrocarbons are broken down to produce smaller more useful molecules?

  Cracking
• Name the two types of cracking

  Catalytic cracking and steam cracking
• What are the conditions for catalytic cracking?

  550°C using a zeolite catalyst containing aluminium oxide and silicon oxide
• What are the conditions for steam cracking?

  550°C and steam
• What is always produced when an alkane undergoes cracking?

  Smaller alkane molecule(s) and an alkene
• Which is more reactive, an alkene or an alkane?

  An alkene
• How can you test for an alkene?

  React it with bromine water
• What do you observe when bromine water is mixed with an alkane?

  There is no colour change; the bromine water remains orange/brown
• What do you observe when bromine water is mixed with an alkene?

  There is a colour change; the bromine water turns colourless
• Why are alkanes cracked?

  Because there is a high demand for fuels and some of the products of cracking are useful as fuels
• What are alkenes used for?

  To produce polymers and as starting materials to produce other chemicals
• What are alkenes?


  Hydrocarbons with a double carbon-carbon bond
• What is the general formula of an alkene?

  CnH2n
• What do saturated hydrocarbons only contain?

  Single bonds
• Why are alkenes unsaturated hydrocarbons?

  Because they contain two fewer hydrogen atoms that the alkane with the same number of carbon atoms
• What are the names of the first four members of the homologous series of alkenes?

  Ethene, propene, butene, pentene
• What is the functional group in alkenes?

  C=C
• What determines the reactions of organic compounds?

  The reactions of the functional group