Edexcel IGCSE Chemistry Crude Oil

CRUDE OIL

  • It is a black thick liquid which takes millions of years to form.
  • It is the mixture of hydrocarbon.
  • Hydrocarbon are the compounds made up of carbon and hydrogen only.
  • The components of the crude oil are important and the crude oil is separated by the process of fractional distillation.

HYDROCARBON PROPERTIES

FRACTIONAL DISTILLATION OF CRUDE OIL

  • Separating the mixtures on the basis of boiling points.
  • It is separated in fractionating column with different substances of similar boiling points

LIQUIFIED GASFUEL
GASOLINE/PETROLCAR FUEL
KEROSENEAIRCRAFT FUEL
DIESEL OILFUEL IN DIESEL ENGINES
RESIDUEMAKING ROADS


L – Look

G – Great

K – Kid

D – Doing

R – Roll

 CRACKING –Thermal decomposition of longer chain hydrocarbon into a shorter chain alkane and alkenes

Thermal Cracking                                               Catalytic Cracking

It is done at a very high temperature                     It is done using a catalyst

CRUDE OIL

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WHY CRACKING

  • Shorter chain alkanes are more in demand as they are more efficient fuel which fractional distillation alone cannot meet.
  • Alkenes are required for polymerization and synthesize other hydrocarbons which fractional distillation cannot meet.

ALKANES – Saturated Hydrocarbon

Carbon-carbon single bond                    made up of carbon and hydrogen

General Formulae  CnH2n+2

Methane – CH4

Ethane – C2H6

Propane – C3H8

Butane – C4H10

Pentane – C5H12

Homologous Series – Members of the same family have similar functional group similar chemical properties and general formulae but different physical property and each members differs from successive by CH2.

COMBUSTION

COMPLETE

INCOMPLETE

  
FUEL IS COMPLETELY BURNED

FUEL IS PARTIALLY BURNED DUE TO LIMITED SUPPLY OF OXYGEN

 

PRODUCES CARBON DIOXIDE AND WATER

PRODUCES CARBON MONOXIDE AND WATER

 

IT IS NOT TOXIC

CARBON MONOXIDE IS TOXIC AS IT DECREASES. THE OXYGEN CARRYING CAPACITY OF RED BLOOD CELLS

 

PRODUCTS OF COMBUSTION

Carbon Dioxide Test   

    Limewater Test     Carbon Dioxide will turn limewater milky

    Water Test

FUNCTIONAL GROUPS
Groups of atoms that give special properties and reactions to the organic molecule

 Functional GroupsExamplesFormation
ALKENES      =Ethene, propene, butene, penteneCracking of crude oil
ALCOHOLS-OHmethanol, ethanol, propanol, butanol, pentanolReaction of alkene with water
CARBOXYLIC ACIDmethanoic acid, ethanoic acid, propanoic acid, butanoic acid.Oxidation of alcohols
ESTERSmethyl ethanoate, ethyl ethanoateReaction of alcohols and carboxylic acid

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References:

BBC Bitesize

Wikipedia

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