Alkenes

Question 1

Why are Alkenes unsaturated hydrocarbons?

Answer 1

Contain at least one C=C double bond

Question 2

C=C bond in Alkene

Answer 2

Region of high electron density, leading to an attack by electrophiles
e.g. H+

Question 3

Electrophile

Answer 3

Electron pair acceptor
e.g. NO2+
H+
H-Br
H2SO4

Question 4

What mechanism do Alkenes go under?

Answer 4

Electrophilic addition

Question 5

Electrophilic Addition reaction with HBr

Answer 5

Conditions: Room temperature
Observations: None

Question 6

Electrophilic Addition reaction with Br2

Answer 6

Conditions: Room temperature
Observation: Decolourisation of bromine (orange/brown to colourless)

Question 7

Electrophilic Addition reaction with H2SO4

Answer 7

Conditions: Room temperature
Observations: Gets hot (exothermic reaction)

Question 8

Electrophilic Addition reaction with Steam (hydration)

Answer 8

Conditions: Acid catalyst (cocnentrated H3PO4, H2SO4)
60atm
300°

Question 9

Monomer

Answer 9

Small reactive molecules join to form polymers

Question 10

Polymers

Answer 10

Large molecule made from a combination of monomers

Question 11

Addition Polymerisation

Answer 11

Unsaturated monomers join to form long saturated cahins

Question 12

Properties of polymers depend on:

Answer 12

1. The monomer from which they are made from
2. The conditions from under which it is made

Question 13

PVC (polyvinylchloride) uses:

Answer 13

Vinyls
Drainpipes

Question 14

How are the properties of PVC modified using a plasticiser?

Answer 14

Small molecules get between the polymer chain, forcing them apart allowing them to slide over eachother

Question 15

Why are addition polymers unreactive?

Answer 15

Since they are saturated with non polar C-C and C-H bonds