alkenes Flashcards
strength of C=C double bonds
stronger than a single bond as it has a sigma and pi bond
pi bond is more reactive as it requires less energy to break
alkenes are more reactive as pi bond breaks faster as sigma bond is stronger
why is there no rotation around a C=C bond
the pi bond is formed by overlap of p orbitals if there was any rotation, the p orbitals would no longer overlap and the pi bond would break
definition of an electrophile
an electron-pair acceptor
what is a positive inductive effect
the ability to release electron density through a covalent bond
why are tertiary carbocations more stable than secondary carbocations
there is a positive inductive effect from the three alkyl groups in tertiary carbocations compared to 2 alkyl groups in secondary carbocations
major and minor products
major product made from a more stable carbocation
minor product made from a less stable carbocation
eg secondary carbocation are more stable than primary carbocations due to the positive inductive effect of the two alkyl groups compared to one
bromine reacts with alkenes, even though bromine is a non-polar molecule. Explain why bromine molecules react with the double bonds in alkenes
the C=C bond is electron rich and induces a dipole in the Br2
partially positive Br attracted to C=C double bond
chemical test for alkenes
Br2
when alkene is present -orange to colourless
when alkene is not present - no visible change
what is an addition polymer
a long chain made from lots of monomers
alkenes are the monomers is addition polymers
draw the polymer of CH2=CH2
—[————-CH2-CH2———]—-
