FC17 Flashcards
What does a compound with Alkene end with?
Ene
Define sigma bond
Formed by direct (end to end) overlap of orbitals
Define pi bonds
Formed by sideways overlap of p-orbitals
Steps of mechanism
Initiation
Propagation
Termination
Define stereoisomers
Compounds with the same structural formula but different arrangements of atoms in space
Why can rotation around a C to C double bond not work
Will destroy the sideways overlap of p-orbitals and break the pi bond. There is not enough energy to do this at RTP
What is needed for E/Z isomers
A C to c double bond
Each of the doubly bonded C must be bonded to 2 different types of atoms/ groups
If higher priority group are on:
Same side of double bond-> Z isomer
Either side of the double bond-> E-isomer
Define Cis-trans isomerism
Where the H atoms are positioned on each of the doubly bonded C atoms
How can an alkene be prepared by dehydration reaction of alcohols
Heat and concentrated H2SO4
Dehydration of H2O can only occur if the hydroxyl group is bonded to a C atom that is bonded to an adjacent C atom which is directly bonded to H
Define addition reaction
The formation of one product from the reaction of 2 or more reactants
How is halogentation using a halogen made
A double bonded compound + a Halogen eg ( Br2)
Which breaks the double bond and forms 2 bonds for the 2 Br atoms
How is halogenation of a hydride halide made
A double bonded compound + a hydrogen halide eg (HBr)
Which breaks the double bond and forms 2 new bonds for the H and Br
How is hydrogenation formed
A double bond compound + H2
Heat and Pt or Ni is needed for catalyst
The double bond breaks to form 2 new bonds for H2
How is hydration made
A double bonded compound + H2O
Steam (300C) and phosphoric acid catalyst needed
The double bond breaks to form 2 new bonds for H and OH
What does curly arrow mean
Movement of an e- pair
What does electrophile mean
Electron pair acceptor
What does all bond breaking involve to form ions
Heterolytic fission
Markowinkoffs rule
In the reaction between an asymmetrical alkene and an asymmetrical reactant the major product is formed from the more stable carbocation intermediate
Example template of carbocation question
2- bromopropane is the major product as it is formed from the more stable 2• (secondary) carbonation intermediate. Whereas the alternative product is formed from the less 1• primary carbonation intermediate.
Define a primary carbocation
The C with the +ve charge is bonded to one or no other C
Define Secondary carbocation
The C atoms with the +ve charge is bonded to 2 other C atoms
Define Tertiary carbocation
The C atom with the +ve charge bonded to 3 other C
The relative stability of carbocation intermediate
3•>2•>1•
