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