Alkenes Flashcards
(21 cards)
Name some properties of alkenes
Trigonal planar
Saturated
Non polar
How is a pi bond formed?
Direct sideways overlap of P orbitals
How do you test for alkenes?
Bromine water goes orange to colourless
Define Stereoisomerism
Same structural formula but different spatial arrangement
Draw an E and Z isomer of but-2-ene
E isomer (trans) has chains oppersite each other
Z isomer (cis) has chains on the same side
What happens when there is more than one group on the double bond when naming E or Z isomers?
The group that has the highest molecular mass takes priority
What 4 things can alkenes have addition reactions with?
Hydrogen
Halogens
Hydrogen halides
Hydration
What reaction mechanism does alkenes undergo?
Electrophilic addition
Draw out the mechanism for electophilic addition between bromine and ethene
CC double bond with 4 hydrogens
Intermediate CC single bond with 4 hydrogens and a bromide with a carbon cation
Final product CC single bond with 4 hydrogens and 2 bromides
What type of bond fission occurs in electrophilic addition?
Heterolytic
How is a major product formed?
The product that is produced on the most stable carbo cation
What is the carbon intermediate called in electrophilic addition?
Carbon cation
What carbon cation is the most stable?
Tertiary
What conditions are needed for polymerisation to occur?
High temperature and pressure
Name the properies of addition polymers
High Mr
Prefix poly
What does n represent in addition polymerisation?
The repeat unit
How do you find the monomer of a polymer?
The repeat unit
How do you find the monomer of a polymer?
The repeat unit
Why are there environmental concerns about using polymers?
They are non biodegradable
What disposal methods make polymers more sustainable?
Bio and photo degradable using uv from sunlight
What is the general formula for an alkene?
CnH2n
