6.2 - Hydrocarbons/ Alkanes, Alkenes

SATURATED hydrocarbons

UNSATURATED hydrocarbons

CnH2n+2

CnH2n

=A measure of the performance of the fuel =higher octane means a more efficient fuel =straight chains are prone to knocking, exploding due to activation energy =knocking is increased by straight chained hydrocarbons, therefore branched molecules burn better ‘higher octane number’

a catalyst is used together with high temperature

useful, break down hydrocarbons to make more useful fuels

temperature and pressure

catalyst, temperature, pressure

Fractional distillation

Inject crude oil vapourised rises cools condenses collected as fractions

To make useful substances such as petrol and diesel

Initiation Propagation Termination

U.V light 300 degrees

the molecule is split by homolytic fission, forming 2 radicals

during the halogenation of alkanes, the radical will then go onto react with eg. methane Rapid process

the end of radical substitution where 2 radicals combine to form a molecule

other radicals can be formed if there’s too much mixture, other products will be formed and therefore have to be separated

Redox reaction one reduction catalyst and one oxidation Molecules bond with the catalyst and elements separate off as a harmless gas

place sample in test tube with drops of bromine water, the more drops needed to go colourless, the more unsaturated

They cant form H bonds because there are no oxygens

Sigma and pi

bonds form between atoms when atomic orbitals overlap and form molecular orbitals

when 2 s orbitals overlap (in a straight line) which is a single covalent bond