chapter 13 Flashcards
alkene
unsaturated hydrocarbons containing atleast one c=c double bond
alkene general formula
c2h2n
from left to right
naming alkene
no of carbons
position of double bond
how many double bonds (diene, triene, tetraene)
each carbon atom has how many electrons to form bonds
4
how many bonds of a carbon is used in sigma bonds
3
what bond makes up the double bond
pi bond
pi bond
sideways overlap of p orbitals above and below c=c double bond
what do pi bonds mean for rotation
rotation is restricted around c=c double bond
stereoisomers
same structural formula, different arrangement of atoms in 3d space
e/z isomerism
isomerism that only occurs in compounds that have
c=c double bond
two different groups attached to each c of the c=c
cis-trans isomerism
isomerism that has a double c=c bond
two different groups attached to each carbon
one of the groups being the same
cahn ingold prelog priority rules
atoms attached to the c atoms of the double bond are given priority based on Ar
if the groups of high priority are on the same side
z isomerism
if groups of high priority are diagonal
e isomerism
why are alkenes more reactivw
pi bond is weaker
electrons are more exposed than sigma electrons
high electron density of c=c
alkenes undergo addition reactions relatively
easy
addition reaction
two reactant molecules join to form 1 product
hydrogenation of alkene formula
ethene/alkene + hydrogen -> Nickel catalyst, 150 degrees to form an alkane
alkenes react with halogens to form
dihaloalkanes
ethene + bromine
1,2-dibromoethane
double bond test with bromine water
bromine decolourised from brick red to colourless
alkene+hydrogen halides at ROOM TEMP
alkene+ hydrogen halide -> haloalkane
hydration reactions of alkenes, what is also needed as a catalysyt
alkenes react with steam in the presence of a phosphoric acid, h3po4 OR sulfuric acid (H₂SO₄),
what are electrophiles attracted to
the high electron density in double bonds
