organic chemistry Flashcards
formula for alkanes
c-c
formula for alkenes
c=c
formula for haloalkane
c-x
formula for alcohol
c-oh
formula for aldehyde
- c=o
- h
formula for ketone
-c(=o)-
formula for carboxylic acid
- c=o
- oh
formula for esters
-c(=o)-o-
cyclohexene with alternate double bonds =
benzene/phenyl
e/z - which is which side of double bond
zed is on ze zame zide
therefore
e is opposite sides of double bond
cis/trans
cis = sisters = same side trans = latin = across = opposite sides
what is homolytic fisson
each bonding atom receives one electron from the bonded pair, forming two radicals
what is heterolytic fisson
one bonding atom receives both electrons from the bonded pair
radical substitution of alkanes example
ch4 +cl2 (UV LIGHT) - ch3cl + hcl
initiation reaction of radical substitution example
cl2 (+UV LIGHT) - 2cl radicals
propagation reactions of radical substitution example
ch4 + cl radical - radical ch3 +hcl
radical ch3 + cl2 - ch3cl +cl radical
termination reactions of radical substitution example
radical ch3 +cl radical - ch3cl
cl radical + cl radical - cl2
radical ch3 + radical ch3 - ch3ch3
possible side products of radical substitution example
could produce any of possible isomers
multiple substitutions can happen
products of termination reactions could also be halogenated
what is a sigma bond
a sigma bond is formed by the overlap of orbital directly between the bonding atoms. they are free to rotate
what happens to boiling points of straight chain alkanes as their length increases
boiling points increase
- as chain length increases, number of electrons in the molecule increases
- van der Waals forces (London) increase
- more energy required to overcome intermolecular forces
what happens to boiling point as isomeric alkanes become more branched
boiling point decreases
- although same number of electrons, branched isomers have a smaller surface area for the london forces to act through
- smaller attraction between molecules
- boiling point decreases
what are the two reaction of alkanes
radical substitution
combustion (complete or incomplete)
what are the products of complete combustion
co2 +h2o
what are the products of incomplete combustion
co + h2o
why aren’t alkanes very reactive
high c-h bond enthalpy and bond is of low polarity
what is the problem with incomplete combustion
production of poisonous co. bonds with haemoglobin preferentially to oxygen
what dissolves what
like dissolves like!
polar dissolves polar and unpolar dissolves unpolar
what is a pi bond
sideways overlap of adjacent p-orbitals above and below the plane of the bonding carbon atoms
what is a double bond
a pi bond and a sigma bond
which is stronger a sigma bond or pi
sigma. pi = 265, sigma = 347. together = 612
what is electrophilic addition
the addition of an electrophile to another molecule
what is an electrophile
an electron pair acceptor
what are the conditions needed for ethene +water(steam) - ethanol
h3po4 catalyst (phosphoric acid)
300degreesC
65atm
which is the more likely carbocation to be formed
tertiary>secondary>primary as tertiary is most stable therefore tertiary is most likely to be major product form hydrohalogenation
what is hydohalogentation
addition of hydrogen and a halogen eg hcl to an alkene to form a haloalkane
what is hydrogenation
addition of hydrogen to an alkene to form an alkane
what is a stereoisomer
a compound with the same structural formula but a different arrangement in space
what is an isomer
a compound with the same molecular formula but a different structural formula
