Chemistry Topic 7 - Organic Chemistry

Organic Chemistry:

Crude Oil, hydrocarbons and alkanes:

Fractional Distillation of crude oil:

• Crude oil is a mixture of hydrocarbons: compounds that contain only C and H atoms.
• Crude oil is separated into fractions by fractional distillation.
• The longest molecules have the strongest intermolecular forces, so they have the highest boiling point and condense nearer the bottom of the fractionating column.
• The fractions of crude oil are called: LPQ, Petrol, Kerosene, Diesel, Heavy Fuel Oil and Bitumen.
• Properties of Small molecules are: Low boiling point, Very volatile, flows easily and Ignites easily.
• Properties of Large molecules are: High boiling point, not very volatile, does not flow easily and does not ignite easily.

Alkanes:

• Alkanes are a homologous series of hydrocarbons.
• Alkanes haven the general formula CnH2n+2
• The first four alkanes are methane (CH4), ethane (C2H6), propane (C3H8) and butane (C4H10).
• The alkanes are saturated hydrocarbons because all the carbon atoms are joined by C-C single bonds.

Cracking:

• Cracking is a reaction which breaks long, less useful hydrocarbons into shorter, more useful hydrocarbons.
• Cracking helps to match supply and demand for the different fractions.
• A long alkane is broken into a shorter alkane (for fuels) and a shorter alkene (a chemical feedstock).

Alkenes:

• Alkenes are a homologous series of hydrocarbons. Alkenes have the general formula CnH2n.
• The…