chem paper 2
what does naoh wffect
only cooh
cooh + naoh
coo-na+. +h20
cooh + mg
(coo-)2mg +h2
cn-cooh
h+
what does it mesn if it has a higher electron density
it can attract cl2 more easily
pi bond
sidewwys overlap of p orbitals
sigma bond
hesd on overlwp of p orbitals
similarities with kekule and delocalised model
both involve the overlappimf of p orbitwls
differences
1) kekule consiste of slternwtimg pi bomds whereas the deloclaised model has the pi bonds delocalised wcross the whole ring
predictions from the delosalised model
1) it does not discoloursie bromine water
2) the dehyrogenwtioj of cyclohexene is -120kjmol so we would expect the dehdrogenetwtiom of benzene ro be -360 but ir is actyally less exothermic thsn oredicted
what do we compwrnth melting poimts of our compounde to in order to idemtify them
a known database
aldedhyde- nitrile
H+ /KCN
what is the normal comonds used in spectroetry
si(ch3)4
when talking about major products what do you say
major product formed from more stable cwrbocwtion
what happnes if yiu add h+ to nh2
nh3+
how to workout mr of x amount of a polyester
work it out then add the remaining mr for what is not included in the polyester
does reaction of aldehyde to carboxylic acid make water
no
what will naco3 react with
only carobylic acid
what will naoh react eith
both phenol and csrbocylic acid
limitwtion of the initiwtiqn progqtiom mechanism
- further wubsitution mwy occur
- subisituion ,ay occur on any cwrbin atom in the cwrbon chwin
what can d2o be used for
to idemtify oh or nh protons
if we have a NH2 and we acc a hydorixide what must we write
either nh2 or nh3 plus
what is homolytic fission
bresking of covalent bond in which each atom recovd 1 electron from the bonding pair
pi vs sigma bind enthalpy
pi has a weaker
how many [O] do you use when going from alchol to ketome
1
what does naco3 reacts with and what does naoh rewct with
what does naoh reacts with
cwrboxylic acids amd phemols
not alchols
what does naco3 react with
only carboylic acids
what is a sogma bond
overlap of obitals between bonding atoms
what is a oi bond
sideways overlap of adjecent orbiatls
what is opticsl isomerism
super non imposbsle mirror images around a chiral carbon
how do you go from ester to carboxylic acid
H+/H20
how many branches does a secondary amide have
1
is benzene unsaturated
yes
nitrile - cooh
h plus and h20
products from an acycl chroide
so2 and hcl
how do you balanace a carboyclic acid with n2co3
both the carboxyl acid snd product have a 2
what do u name first alchol or alkene
alchol
how does hb act as an electrophile
the h in hbr accepets a pair of electrons
how do you check phrity
obtain mp usimg mp apprartus compare ranges to known value if pure narorr mp range if impure range widens
how to go from nitrile to carboxylic acid
HCL (aq) and H20(l)
pehmol plus bro,mine
phenol with 3 BR
tlc method
1) mark a baslime that is insoluble im mobile phase
2) mobile phase must be in a liquid solvent which wmino acid dissolves in
3) solvent must be below baseline
4) stationwry phase is the adsorbwnr substsnce on TLC plwte
5) dot sample on baseline
6) lesve ro run inna tank with lid on
7) remove plare approx 1cm before solvent resches top
8) mark solvent dromt wmd lesve to dry
9) use UV ligjt to make spots visable
why is silica used
unrewctive
what is the si for,uka
si (ch3)4
why is si(ch3)4 used
inert wnd unrewctige so will not interfee with substance
why add d20
replaces the h onnthe oh or nh so pesk not shown in secojd trace
how do i workout mew mass
percentage yield x moles
how do i workout old mass
moles/ percentwge yield
differences between kekule and delocalised
kekule has alternating pi bonds whereas delocalised has a pi rung which all p orbitals overlap
what does benznene not do
resct rewdily by addition
how do approach the ch with a 4 carbon ajcent
ch3 on one side amd h on the other
how to go from a haloalkane to a nitrile
excess nh3 and ethanol
in equation write 2nh3
purfication of a crystal steps
1) dissolve in a minium volume of hot solvent
2) cool solution and filter solid
3) wash with cold water and dry
purity check steps
1) ohtain mp
2) compare to known vakues
3) if pure it will have a sharp mp close to the data book value
4) if impure will have a wider mp range
purifcation of a liquid
1) add to a seperating funnel
2) organic layer settles om top ( if density is less than water )
3) dry with an anhydrous salt
4) redistill
tlc steps
1) a pencil line is drawn horizontally about 1 cm from the base of the plate
2) a spot of sample is added to the line and allowed to dry
3) the plste is then added to a beaker containing a solvent at the bottom
4) ths solvent is allowed to rise up the plate
ahat is the retention time
the time taken for component to travel through the collum
which is then compwred to a known database of known values
microgrames/ml ------ g/dm cubed
10^-6
x1000
then divide by mr
to get moldm3
naoh + nahbr+ h2so4--> naoh + nahso4 + h20
h