organic chemistry Flashcards
definitions
homologus series
a family of compounds with similar chemical properties where each successive member differs by an addition of a CH2 group
functional group
part of the organic molecule responsible for its chemical reactivity
structural isomerism
molecules with the same molecular formula but a different structural formula
stereoisomerism
molecules with the same structural formula but a different arrangement of atoms in space
what is a priority group?
the group attached to a carbon with the highest atomic number
z isomer
if the priority groups are on the same side as each other
e isomer
if the priority groups are on the opposite sides of each other
cis/trans isomerism
applies if each carbon is bonded to a hydrogen
cis isomer
whether the priority groups are on the same side
trans isomer
if the priority groups are on a different side to each other
how do you know if a molecule has stereoisomerism
- must have a double bond
- each carbon in the double bond must be bonded to two different groups
- for cis/trans, each carbon in the double bond must be bonded to one hydrogen
list alkene reactions
hydrogenation
hydration
halogenation
hydrogen halides
additional polymerasation
what catalyst do you use in a hydrogenation reaction and at what temp?
nickel at 150 degrees / 423k
what catalyst do you use in a hydration reaction
hydrogen phosphate (H3PO4)
define electrophile
an electron pair acceptor
mechanism name of halogenation for alkenes
electrophilic addition
mechanism name for halogenation of alkanes
free radical substitution
mechanism for hydrogen halides
electrophilic addition
polymer
long chain molecules found from many repeat units of monomers eg polyethene
monomer
a small molecule that combines with many other monomers to form a polymer eg ethene
additional polymerasation
formation of polymers by repeated addition reactions of many unsaturated alkane molecules (monomers)
feedstock recycling
breaking polymer down into small molecules which allow them to be used to make something else
why are alcohols soluble in water?
because they form hydrogen bonds with water
why are alchohols less volatile?
- less volatile and a higher b.p. than the corresponding alkane because they turn into gas quicker and for h2 bonds unlike other alkanes which requre more energy to break
fermentation of sugars
C6H12O6 ——-> 2C2H5OH + 2CO2
oxidising agent for alcohols
K2Cr2O7 / H2SO4
what do primary oxidation alcohols form and what conditions do they use?
they form an aldehyde (prefix - al) and go under distillation
if primary oxidation uses reflux what does it form
carboxylic acid (prefix - oic)
what do secondary oxidation alcohols form and what conditions do they use?
they form a kentone (prefix - one) and they use reflux conditions
define nucleophile
an electron pair donor
what does substitution of alcohols form
haloalkane + NaSO4 + water
what is used in the substitution of alcohols
sodium halide + sulfuric acid
what condition is used in the dehydration of alcohols?
reflux
what happens as we increase the carbon chain length
- larger surface area
- so more surface points of contact
- more electrons
- stronger london forces
- more energy required to break the LFs
- hence b.p. increases
what happens as we increase the branching
- fewer surface points of contact
- weaker london forces
- less energy required to break the LFs
- so b.p. decreases
volatility meaning
turns into a gas very quickly
why are alcohols very soluble in water?
because they form hydrogen bonds with water
- alkanes are non-polar
why are alcohols less volatile but have a higher boiling point than the corresponding alkane?
- alkanes turn into a gas quicker
- since alcohols form hydrogen bonds, they are less volatile as they don’t turn into a gas quickly since their hydrogen bonds require more energy to break than the London forces between the alkanes
what’s made from polyethene
- plastic straws
- plastic bags
- plastic bottles
what’s made from pvc (poly vinyl chloride)
- window frames
- gutter pipes
- cling film
- laminated flooring
what’s made from polypropene
- bottle cap lids
- children’s toys eg lego
what can be made from polystyrene
- styrofoam
what can be made from PTFE (polytetrafluroethene)
- waterproof/burnproof coating eg on coats, pans, cars
- insulating tape
downside of burning pvc
releases tcl - a toxic gas
what does hydrolysis of haloalkanes form?
haloalkanes + h20 —-> alcohol + hydrogen halide
mechanism for substitution of haloalkanes
nucleophilic substitution
nucleophile definition
an electron pair donor
homolytic fission def.
the breaking of a covalent bond with one of the bonded electrons going to each atom, forming two radicals
heterolytic fission def.
the breaking of a covalent bond forming a cation (+) and an anion (-)
