Alkenes Flashcards
Why are Alkenes unsaturated hydrocarbons?
Contain at least one C=C double bond
C=C bond in Alkene
Region of high electron density, leading to an attack by electrophiles
e.g. H+
Electrophile
Electron pair acceptor
e.g. NO2+
H+
H-Br
H2SO4
What mechanism do Alkenes go under?
Electrophilic addition
Electrophilic Addition reaction with HBr
Conditions: Room temperature
Observations: None
Electrophilic Addition reaction with Br2
Conditions: Room temperature
Observation: Decolourisation of bromine (orange/brown to colourless)
Electrophilic Addition reaction with H2SO4
Conditions: Room temperature
Observations: Gets hot (exothermic reaction)
Electrophilic Addition reaction with Steam (hydration)
Conditions: Acid catalyst (cocnentrated H3PO4, H2SO4)
60atm
300°
Monomer
Small reactive molecules join to form polymers
Polymers
Large molecule made from a combination of monomers
Addition Polymerisation
Unsaturated monomers join to form long saturated cahins
Properties of polymers depend on:
- The monomer from which they are made from
- The conditions from under which it is made
PVC (polyvinylchloride) uses:
Vinyls
Drainpipes
How are the properties of PVC modified using a plasticiser?
Small molecules get between the polymer chain, forcing them apart allowing them to slide over eachother
Why are addition polymers unreactive?
Since they are saturated with non polar C-C and C-H bonds