paper 2 mistakes Flashcards
which compound is used as a standard for NMR chemical shifts
Si(CH3)4
what do nucleophiles react with
electron pair acceptor (centre of electron deficiency)
markoffnikoffs rule
hydrogen more likely to bond to the carbon with the greatest number of hydrogens
structeral isomer
same molecular formula different structeral formula
amino acid + acyl chloride
N group becomes amide
how to turn a ketone into an ester
oxidise to carboxylic acid
add alchol
evidence for delocalised model
c-c and c=c different lenghts, X Ray differaction shows benzene is a regualr hexagon
^H hydrogenation less exothermic than expected, bonds more stable than alkenes
benzine didnt react with hydrogen hallide, bromine, H2SO4, no double bonds, cannot undergo electrophilic addition
deloaclised model of benzene
each C has 3 pi bonds, 120 degrees
leaves a spare electron in 2p orbital
2p orbitals overlap, above and below ring forming pi bonds
electrons are delocalised
why do CFSs reahc stratosphere
high bond enthalpies so not broken down in lower atmosphere, broekn down by UV in stratosphere
break down of ozone by CFC CCl3F
on post it note
what is phenol and what does this mean
weak acid
reacts with NaOH but not NA2CO3
when phenol reacts with Br2
Br2 decolourised and white ppt- no catalyst
2, 4 groups
electron donating
OH NH2
increase electron density
3,5 groups
electron withdrawing
NO2
decreases electron density
synthesis of an organic liquid
once reaction complete, pour mixtures into seperating funnel
neutralise any excess acid using sodium carbonate, stops bubbling when neutral
allow 2 layers to settle
use density to establish layers, or add water and aq layer will get bigger
collect wanted layer
add drying agent (anhydrous CaCl2)
distil dried product and collect fraction that comes off at stated bioling point
purity of organic liquid
boiling point should match known data, impurities widen narrow bp range
run TLC, measure Rf compare to known data/ run for pure sample
run NMR/ mass spec compare to database of known pure compounds
synthesis of organic solid
purify by recrystlaisation
dissolve in min vol of hot solvent
cool in ice to recrysatlise (impurities stay in solution)
filter using Buchner funnel
wash with cold solvent
dry
purity of organic solid
measure mp, compare to data values
should melt sharply over narrow range
TLC
how to make primary amine
haloalkanes with excess ammonia in ehtnaol
test for phenols
test acidity
add Na2CO3-no effervescence
explain relative resistance to chloronation of benzene vs alkene
alkene: electrons are localised
electron density higher
more susceptible to electrophilic attack
polarises Cl2 more
benzene: deloaclised
electron density lower
cannot polarise
other products formed when carboxylioc acid + SOCl2
acyl chloride, SO2, HCl
explain the use of two denatured compounds in NMR spectroscopy
CDCl3 used as solvent
D2O used to identify OH and NH protons
