alkenes Flashcards
(26 cards)
are alkenes saturated or unsaturated
unsaturated
what is a pi bond
indirect overlap of orbitals
what is a sigma bond
simple covalent bond with direct overlap of orbitals
why are alkenes more reactive than alkanes
-as it has a C=C
-double bonds have a high electron density where the electrons are localised between the C=C
-this makes them more reactive towards a strong electron acceptor
how does a molecule show isomerism
-if it has C=C
-if it has two different groups on each carbon
what does a C=C bond do in isomerism
restricts rotation
why is C=C vulnerable to electrophilic attack
as it contains pi bonds which have a high density of electrons
what are the products and reactants in hydrogenation
alkene -> alkane
reagent of hydrogenation
hydrogen
conditions of hydrogenation
Ni catalyst
reactants and products of halogénation
haloalkane
reagent of halogénation
HBr or Br
conditions of halogénation
room temp
reactants and products of hydration
alkene -> alcohol
reagent of hydration
steam
conditions of hydration
high temp, conc H3PO4
what are the priority rules
- group witj highest atomic number has priority
-compare groups closets to C=C
definition of stereoisomerism
same structural formula, different arrangement in space
effect of E isomerism on physical properties
(Cl)
-molecule is non-polar
-polar C-Cl are on different sides
-dipoles cancel out
-only london forces so lower bp
effect of Z isomerism on physical properties
(Cl)
-polar
-C-Cl are on same side
-contains london forces and permanent dipole dipole so higher bp
carbocation rule
Br (halogen) will be added to the carbon with the least number of Hydrogens
stability order
tertiary > secondary > primary
what is the colour change in the reaction halogénation of an alkene and bromine
orange to colourless
advantages of dating combustion as a method for disposing polymers
can produce energy and use as organic feedstock
