3.3.4 - Alkenes Flashcards
Test for alkenes (bromine)
- Add bromine water
- Brown to colourless
Markovnikov’s rule
Carbocation forms on carbon with most alkyl groups attached
Draw the electrophilic addition mechanism to form an alkyl hydrogen sulphate intermediary
- C=C bond attacks H+ of sulphuric acid
- Oxygen lone pair of sulphuric acid joins to carbocation
Electrophilic addition reaction conditions to form an alkyl hydrogen sulphate intermediary (2)
- Cold
- Concentrated sulfuric acid
2 ways of getting alcohol from alkenes
- Alkene —> alkyl hydrogen sulfate —-> alcohol
- Alkene —–> alcohol
Alkene straight to alcohol reaction conditions (4)
- Steam
- 300 degrees
- 60 atm
- H3PO4 catalyst
Hydrolysis of alkyl hydrogen sulphates reaction and products
- Add warm water
- Forms alcohol + sulphuric acid.
Why is sulfuric acid a catalyst?
Reformed at the end of the reaction
How do you draw a repeating unit? (3)
- Remove double bond from monomer
- Draw brackets with bonds coming out of it
- Write n next to the brackets
The longer the polyalkene chain… (2)
- The higher the boiling point
- More rigid
High pressure polymerisation forms…
Branched polymers with weak IMFs
Low pressure polymerisation forms…
Straight chain polymers, with strong IMFs
Why are polymers non biodegradable?
Non-polar covalent bonds means they are unreactive
Why is there an attraction between C=C and Br2?
1.Double bond = electron dense
2.Br2 becomes polarised, with the delta positive Br getting attracted to the bond
What do plasticisers do and how do they work? (3)
- Make polymers less brittle/waterproof
- By fitting between chains and weakening IMFs
- Allowing for the layers to slide over each other
