alkenes

Question 1

what is a test for alkenes?

Answer 1

add bromine water, orange to colourless change

Question 2

what does unsaturated mean?

Answer 2

contains at least one c=c bond

Question 3

what is stereoisomerism?

Answer 3

same structural formula but atoms/groups have different spatial arrangement

Question 4

what is a Z isomer?

Answer 4

the substituted groups are on the same side of the double bond

Question 5

what is an E isomer?

Answer 5

the substituted groups are on opposite sides of the double bond

Question 6

what happens when unsymmetrical alkenes react with hydrogen halides?

Answer 6

2 different products are produced
the amount of the 2 products are determined by the stability of the carbocation intermediate
the more alkyl groups bonded to the carbocation, the MORE stable the intermediate is because the alkyl group pushes e- towards the positive carbocation

Question 7

how do you know sulfuric acid acts as a catalyst?

Answer 7

during the hydrolysis reaction, sulfuric acid is reformed and an alcohol is produced

Question 8

why are poly(alkanes) unreactive?

Answer 8

they are saturated and non polar

Question 9

what are the properties of polyalkenes?

Answer 9

*most polyalkene chains are nonpolar so they have van der waal forces between chains
*the longer the chain and the closer they are to each other, the more van der waals
*polymer chains which are shorter and have a lot of branching are often weaker and more flexible as they cannot be compact
*polymers with little branching are more rigid and stronger
*some have halogens so can form very strong permanent dipole dipole forces

Question 10

what are some properties of plasticisers?

Answer 10

plasticisers make polymers more flexible as they slide between the polymer chains, pushing them apart
this weakens the intermolecular forces between the chains so they can slide over each other