3.3.4 Alkenes

Why are alkenes susceptible to attack from electrophiles

C=C double bond = area of high electron density

what is formed during electrophilic addition

a carbocation intermediate

which carbocation intermediate is most stable

tertiary carbocation is most stable. more stable than secondary which is more stable than primary. Tertiary = 3 alkyl groups attached to the carbon

What is formed from what intermediate product?

the major product is formed via the most stable carbocation. the minor product is formed via the less stable carbocation

why is there attraction between double bonds and electrophiles.

the C=C bond has a high electron density and the electrophile becomes polarised so the more delta positive end is attracted to the electrons in the bond as they have a negative charge.

what are polymers and why are they bad for the environment

they are large alkane molecules which are unreactive and do not biodegrade. when burnt they produce harmful combustion products that pollute the environment.

what is a polymer

a long chain molecule made from lots of small molecules joined together

what is a monomer

a small molecule that joins together with other monomers to make polymers

What do addition polymers not have

they don’t have any double bonds and are fully saturated

how do draw repeating unit

H structure with no double bonds. using brackets and n. extend the single bonds outside the bracket

how do plasticisers work

they make polymers more flexible by disrupting VDW forces between molecules, making them weaker

what can PVC be used to make before/after plasticiser is added

drainpipes/pool liners