C14 Alkenes Flashcards
What is an alkene?
Alkenes are unsaturated hydrocarbons and they contain a double c-c bond
What is the general formula of alkenes?
CnH2n
What is a property that double bonds contain in alkenes?
Double bonds have a high electron density and this makes alkenes fairly reactive making it susceptible to attack from electrophiles
What are the observable changes for the test for alkenes using bromine water?
Turns the solution from orange-brown to colourless
What is the main mechanism that occurs when alkenes are used?
Electrophillic addition
Are electrophiles electron donors or acceptors?
These are electron acceptors
What are electrophiles?
They are electron pair acceptors that are deficient in electrons and are attached to the double bond
Name some of the most common electrophiles
HBr
Br2
H2SO4
What do these common electrophiles produce?
They can be used to form alkyl hydrogensulphates or halogenoalkanes
What is the amount of 2 products determined by?
It is determined by the stability of the carbocation intermediate
What happens when more alkyl groups are bonded to the carbocation?
A more stable intermediate and this is due to the groups pushing electrons towards the positive carbocation stabilising it
A more stable carbocation =
More likely it will form
In order of least to most stable order carbocations
Primary
Secondary
Tertiary
What do alkenes react with to form alkyl hydrogen sulfates?
Cold concentrated sulfuric acid
How can alcohol be made via using alkyl hydrogen sulfates with sulfuric acid?
By adding cold water to warm alkyl hydrogen sulfate it will form a alcohol and reform sulfuric acid
How is the process of making an alkyl hydrogen sulfate with sulfuric acid done?
Via Hydrolysis
What does sulfuric acid acts as and why?
It acts as a catalyst as it is reformed
What are addition polymers?
Addition polymers are produced from alkenes where the double bond is broken to form a repeating unit
What is key to show when displaying a addition polymer?
The repeating unit must always be shown with extended bonds through the brackets showing that it bonds to other repeating units
What type of polymers form under high pressure and temperature?
Branched chain polymers are produced with weak IF
What type of polymer is produced under lower temperature and pressure?
Straight chain polymers with strong IF as they are closer together so more VDW
What are polymers?
They are unreactive hydrocarbon chains with multiple strong, non polar covalent bonds
What are plasticisers and what are they used for?
They added to polymers to change their properties
How do plasticisers work t?
They make the polymers more flexible by allowing the polymer chains to slide between and push them apart
