ORGANIC CHEMISTRY: alkenes Flashcards
what is an alkene?
unsaturated hydrocarbon with C=C double bond
what is the general formula of an alkene?
CnH2n
why is there no rotation around the C=C double bond?
due to the pi bonds. there is electron density above and below the single bonds, which holds the carbon atoms in place.
Are they more or less reactive than alkanes? why?
More reactive due to the high electron density of double bond and the fact that the pi bond is slightly easier to break.
what intermolecular forces of attraction do they have?
Van der waals due to non polar bonds
are they soluble in water?
no because non polar bonds
name and describe the 3 kinds of isomers?
chain isomers ( branched chains)
position isomers ( C=C on different carbon atoms)
geometric isomers (E/Z isomerism)
what is an electrophile?
electron deficient atoms which accept a pair of electrons from the C=C double bond.
what is the most stable kind of carbocation intermediate?
alkyl groups have a positive inductive effect, so the most stable carbocation is the one bonded to most of the carbon atoms (alkyl) eg tertiary strucutre
what conditions are needed for the electrophilic addition of H2O to an alkene?
add a catalyst usually phosphoric acid
what is the product formed when water molecule is added to ethene?
an alcohol
draw a mechanism for the addition of water to ethene?
check pmt
what are the conditions needed for the electrophilic addition fo hydrogen halide to an alkene?
room temperature
what are the conditions needed for the electrophilic addition of a halogen molecule to an alkene?
room temperature and organic solvent
How does a molecule with a non polar bond react as if it is an electrophile?
C=C double bond with a high electron density induces a temporary dipole in the halogen molecule. The partially + charge is attracted to the double bond.
