B3 - organics Flashcards
what is a sigma bond
ends overlap
single bond
1 orbital from each atom overlaps
strong
what is a pi bond
orbitals overlap side by side
weak bond
what are the 3 type of structural isomers
chain - branches
position - functional group
functional group
what are the two types of stereo isomers
E/Z and optical
what are E/Z isomers
where the pi bond cannot rotate
E - highest rfm group on different sides of the pi bond
Z - same side
what are optical isomers
carbon with 4 different groups bonded to it
rotates light in opposite directions
general formula of alkanes
Cn H2n+2
what is the molecular formula
the actual number of atoms of each element in a molecule
what is the empirical formula
simplest whole number ratio of the atoms in a molecule
what is a homologous series
same general formula and same functional group
what is the equation for atom economy
molecular mass of desired products / mass of products
x 100
what type of IMFS do alkanes have
london forces
what is the trend of solubility in alkanes
soluble in non-polar solutions
cyclohexane
as alkanes are non-polar
what is the trend with boiling points with alkanes
boiling point increases with chain length
more electrons
stronger London forces
what is the trend with chain branches and boiling points with alkanes
bpt decreases
less surface area in contact
IMFs are weaker
what is the equation for complete combustion with alkanes
alkane + oxygen —> water + carbon dioxide
what is the mechanism that alkanes do
free radical substiution
why is UV light required when reacting alkanes and halogens
to break the bond in the X2 to form 2 free radicals
to allow it to undergo homolytic fission
what are the three stages of free radical substitution
initiation
propagation
termination
describe free radical substitution in steps
Br2 → 2Br*
CH4 + Br* → *CH3 + HBr
}
CH3 + Br2 → CH3Br + Br }
2*CH3 → CH3CH3
definition of aliphatic
straight / branched hydrocarbon
definition of alicyclic
cyclical hydrocarbon
definition of aromatic
cyclical and alternating double and single bond hydrocarbon
what is the test for alkenes
add Br2 - bromine water
solution turns from orange to colourless
what is the test for haloalkanes
add AgNO3
forms white cream yellow ppt
what is the test for alcohols
add PCl5
steamy white flames - produces HCl
test for aldehydes/ketones
add 2,4 DNPH
yellow ppt forms
test for aldehydes
from yellow ppt add acidified Cr207 2-
turns from orange to green
test for carboxylic acids
add universal indicator
turns red/orange
what is an electrophile
electron pair acceptor
what is a nucleophile
electron pair donor
what is the mechanism from alkane to haloalkane
free radical substitution
what are the conditions needed for alkane to haloalkane
UV light
what is the mechanism for alkenes to alkanes
