Alkenes 3.3.4 Flashcards
Alkenes have a higher bond enthalpy than alkanes but why are alkenes more reactive than alkanes
In alkenes, there is a region of high electron density on the C=C bond
What is an electrophile
What are some examples
What is this reaction called
Electron pair acceptor
Polar meolcuels and positively charged ions
Electrophillic addition
Electrophile Samsung notes
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What are the 3 types of carbocations explain the groups attached to each
Which one is most stable and why
Primary (1°) carbocation (2 H and one R)
Secondary (2°) carbocation (1H and 2 R)
Tertiary (3°) carbonation (3 R)
Tertiary is most stable as alkyl groups are electron donators and this makes the carbon atom less electron deficient
What is the test for alkene
Add bromine water to a test tube containing alkene and shake
Solution turns from orange to colourless
Alkenes react with concentrated sulfuric acid to form..
This then reacts with steam to form…
What mechanism is this
Alkenes react with concentrated sulfuric acid to form alkyl Hydrogen sulfate
This then reacts with steam to form alcohol
Electrophillic addition
Sulfuric acid SAMSUNG NOTES
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What happens in an additional polymerisation reaction
Alkenes react with other alkenes to form polymers
What is the percentage atom economy in addition polymerisation reactions
100%
Why is the polymer formed in addition polymerisation unreactive
The double bind is broken
Explain how branching effects properties of polymers
-Polymers with no/fewer branches can pack closer together so stronger intermolecular forces between moelucles (a strong rigid molecule like poly(ethene) is formed)
-Polymers with large branches cannot pack close together, weaker intermolecular forces betweeb moelcules, a flexible material like poly(styrene) is formed
Why do Polymers melt but not break
There are strong covalent bonds betweeb each individual monomer in a polymer
There are weak van der waals forces between polymer chains which cab be overcome
How can the properties of polymers be modified
Plasticisers molecules get betweeb polymer chains and push then apart which reduces the strength of van der waals forces which makes it more flexible
