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1.6 ALKANES


· Alkanes are saturated hydrocarbons = only contains single C-C bonds.
· General formula: CnH2n+2
· Cycloalkanes ­ when carbon atoms from a ring other than benzene,
formula: CNH2n (same as alkenes because end hydrogens not required)



NON-POLAR INSOLUBLE
·difference in ·they only have vdW
electronegativty forces between…

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· Different components are drawn off at different levels in
fractionating column because of temperature gradient
· Fractional distillation is a physical process so no covalent
bonds within the molecules are broken. It's the van der Waals
forces between molecules that are broken during vaporisation
and reform on condensing.

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Cracking ­ long chain alkanes split into shorter chain alkanes and alkenes by breaking the
C-C bonds

Why?
· Because shorter chains are economically more valuable and in 3
demand, so to meet demand cracking is used. 2 useful results:
1. Shorter, more useful chains produced (espec. Petrol)
2. Some…

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Combustion

· Shorter chain alkanes burn completely in excess oxygen to form
combustion products CO2 and H2O
E.g.


CH4 2O2 2H2O CO2 EXOTHERMIC




· Combustion reactions give out heat and the more
carbons present, the greater the heat output.
· Makes them good as fuels (which release heat energy when…

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Removing sullfur

· Some chimneys used calcium oxide CaO, or limestone CaCO3
to absorb the sulphur dioxide.
· Produces gypsum CaSO4, which is used as a plaster
· FLUE GAS DESULFURISATION

Catalytic converters ­ device fitted to car exhaust containing a catalyst where NOx's
are reduced to N2 and CO,…

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