ALKENES Flashcards
What are alkenes? (1)
alkenes are unsaturated hydrocarbons.
what is the general formula for an alkene? (1)
the general formula is Cn +H2n
why are alkenes unsaturated? (1)
because they can make more bonds with extra atoms in addition reactions.
why do alkenes have a high electron density? (1)
because there are two pairs of electrons in the C=C double bond, this makes alkenes pretty reactive.
what happens to alkenes in electrophilic reactions? (2)
the double bonds open up and atoms are added to the carbon atoms.
why can alkenes participate in electrophilic addition reactions? (1)
because the double bond has got plenty of electrons and is easily attacked by electrophiles.
what are electrophiles? (1)
electrophiles are electron-pair acceptors, they are a short of electrons and are attracted to areas where there are lots of them.
what are some examples of electrophiles? (2)
positively charged ions
polar molecules
what do alkenes undergo electrophilic addition reactions with? (1)
hydrogen halides to form halogenoalkanes
what happens if an unsymmetrical alkene reacts with hydrogen halide? (1)
it produces two products, the amount of each product depends on how stable the carbocation formed in the middle of the reaction is (called the carbocation intermediate)
what carbocations are more stable? (1)
carbocations with more alkyl groups are more stable because the alkyl groups feed electrons towards the positive charge, the more stable carbocation is much more likely to form.
what other chemicals can undergo electrophilic addition with alkenes? (1)
alkenes reacted with cold concentrated sulfuric acid for form alkyl hydrogen sulfates.
how can you convert alkyl hydrogen sulfates from the reaction? (1)
they can form alcohols by adding water and warming the reaction mixture.
