Chapter 13-Alkenes Flashcards
(30 cards)
what is the functional group of alkenes
c=c
what does the double bond consist of
a pi bond and a sigma bond
what is the shape and angle around the c=c bond
trigonal planar
120
are alkenes more reactive then alkanes and why
yes as the bond has a smaller bond enthalpy
what is an electrophile
an atom or group of atoms that accept an electron pair from an electron rich centre
what is a stereoisomer
have the same structural formula but a different arrangements of the atoms in space
what are the 2 types of stereoisomerism
E/Z isomerism
optical isomerism
what are the 2 conditons of e/z isomers
there is a c=c bond
there are 2 different groups attached
give an example of e/z isomers
H3C. H
\ /
C=C
/ \
H CH3
E-but-2-ene.
H3C. CH3
\ /
C=C
/ \
H H
Z-but-2-ene
what is a cis isomer
has both hydrogens atoms on the same side of double bond
what is a trans isomer
has both hydrogens on opposite side of double bond
what happens during a addition reaction of alkenes
small molecules adds across bond casuing pi bond to break and new sigma bonds to form
if you add hydrogen to a alkene what do you make
alkane
what happens if you react a alkene with a halogen
forms dihaloalkanes
how do you test for unsatuation
add orange bromine water
should turn colourless if double bond present
what hapens when alkenes react with hydrogen bromide
they form bromoalkanes
what happens when alkenes react with steam
they form alcohols
what kind of addition do alkenes use
electrophilic
how do you draw an electrophilic addition
look at notes or page 83 in textbook
what is the equation for addition of propane to bromine
CH3CH=CH2+BR2 —> CH3CHBrCH2Br
how does addition of unsymmetrical alkenes work
it forms a major and a minor product
the major product more stable atom
what is the most stable secondary, primary or tertiary carbocation
tertiary
draw elecrtophilic addition with an unsymmetrical alkene
look at page 84
what are addition polymers
very large molecules formed by joining together many thousands of alkene molecules
