[Doctor.]

It's almost exam time again guys! SOOOO I though we should get this thread started before it's too late .

Just discuss whatever you want, related towards CHEM4! Share resources or even just tell us all what part of the specification you're revising and maybe others can chip in etc!


So to start:

-Kinetics, Equilibria and most of Acids and Bases has been covered! Just made notes at the moment, and will be doing questions after finishing notes in a week today!


How about everyone else? (I find the acids and bases bit quite hard, especially the Buffers)


LA MARK SCHEME

Originally Posted by Josh1993
Unofficial mark scheme.
1a)
i)0.47,0.170
ii)sraightforward.
iii)equal amount of mols on both
sides.
iv)52.1
b)
i) D
ii)B
iii)A
iv)C
2) 4.5*10^-4
4.5*10^-3
4.33*10^-2
b) rate = 4.44 mol^-2dm^6s^-1
a) proton donor.
b) i) ii) iii) BBAABA in that order.
c) 37.8 cm^3
d) i) 4.52
ii) standard
iii)2.64
iv)4.48.
4 a) mechanism as standard
(methylpropanoate)
b) i)1,5-pentanediol
ii) simple enough.
iii) base hydrolysis (base is usually
ignored). acts as nucleophile blah blah
c i) ethanoic acid
ii)not sure.
iii) no HCl , not as vigourous etc....
d) can't draw
e) i ) ester
ii) 11
iii) look at formula sheet.
f) i) 1 and 3 ticked
ii) pink ------> colourless
5) a)Nuclephyllic addition.
B)2-Bromobutanenitrile
c) NH3 , Excess , nucleophyllic
substitiution.
d i) zwitterion
ii) stronger forces of attraction , Vdw in
the other molecule etc....
e) i) NH2CH2COOCH2CH3
ii) COH(CH3)2CONH2
iii) NH2CH2CH2CH2COOH
iii) CH3CH2CH(N(CH3)2)COOH hard
without drawing
6 a) AlCl3 + CH3COCl ----------------->
[AlCl4]- + CH3CO+
AlCl4 - + H+ ---------------> AlCl3 + HCl
Phenylethanone
b) C6H5CO+
c) Inductive effects?? I should really
know this but oh well.
7 a) propan-1-ol conc H2SO4
orange-----> green
propanal , fehlings/tollens , brick red
PPT, silver mirror
propanoic acid , Na2CO3 ,
Effervesence(CO2)
Chloropropane , dil HNO3 , NaOH ,
AgNO3
b) oxidation, state wavenumber of
c=o,diffrent affinites/solubilities.
8) 1,4 dinitrobenzene
1,2 dinitrobenzene
double bond with 4 methyl groups
around it.
cyclocompund (cyclohexane)
see post on next page(someone
uploaded pictures.))
3 ethyl groups as bonded to N.
c(CH3)3NHCH3
Feel free to amend and add to this as
some questions I dont know (only a
couple). This is very rushed so likely to
be mistakes.
This was posted from The Student
Room's iPhone/iPad App

[Sorro10]

Ill be revising this... next year

[Doctor.]

(Original post by Sorro10)
Ill be revising this... next year

Good to hear . Buffers is killing me

[Sorro10]

(Original post by Doctor.)
Good to hear . Buffers is killing me

:P CHEM4 is the hardest?

[Doctor.]

(Original post by Sorro10)
:P CHEM4 is the hardest?

Depends, it's got a lot more -apply to the question type of stuff. Which isn't too bad I guess, it's just long and need to know a lot of stuff!

CHEM5 is slightly nicer, in terms of smaller...but the downside being you have to remember so much information. Chemistry A2 is hard in general

[Bubbles94]

CHEM5 will be alright i think.. but CHEM4 was terrible...
be careful about resitting CHEM4.. its so difficult to revise alongside CHEM5.. and if you put too much attention on CHEM4.. you could mess up CHEM5, and we only get one shot at CHEM5 :/

[thegodofgod]

(Original post by Bubbles94)
CHEM5 will be alright i think.. but CHEM4 was terrible...
be careful about resitting CHEM4.. its so difficult to revise alongside CHEM5.. and if you put too much attention on CHEM4.. you could mess up CHEM5, and we only get one shot at CHEM5 :/

I'm doing BIOL2, BIOL5, CHEM4, CHEM5 this summer

[Doctor.]

(Original post by thegodofgod)
I'm doing BIOL2, BIOL5, CHEM4, CHEM5 this summer

Aw don't worry, CHEM5 is really not too bad! Mainly revision/memory. It's more like a review of all the AS and a little of A2, plus some new content which isn't too bad
CHEM4 is a shocker for me

(Original post by Bubbles94)
CHEM5 will be alright i think.. but CHEM4 was terrible...
be careful about resitting CHEM4.. its so difficult to revise alongside CHEM5.. and if you put too much attention on CHEM4.. you could mess up CHEM5, and we only get one shot at CHEM5 :/

I've pretty much finished making notes for CHEM4. Feel like I don't know much about Amines and Polymers really . The first chapers are not too bad though NMR....I know It enough to be able to do questions on it BUT not enough to have an open conversation about It...if thag makes sense lolol

[Doctor.]

Just going though Acids & Bases atm, it's not too bad but the buffers -Not fun

There is something that is slightly confusing me. On alevelchemistry.co.uk, the notes talk about dilution factors etc...I have not seen ANYTHING about dilution on the spec for CHEM4

[MuffinMonster]

Failing to remember all the reagents/reactions and infrared spec killed me in Jan

[Doctor.]

(Original post by MuffinMonster)
Failing to remember all the reagents/reactions and infrared spec killed me in Jan

reagents are starting to annoy now, just doing questions of Aromatic compounds etc

[clownfish]

Best advice i can give on reagents is draw a flow chart. One for all the aromatics, and one for the rest of organic. Then label the arrows between each type of compound with the reagents and mechanism needed to get from one to the other.

I did this several times and that helped me get my A.

[thegodofgod]

(Original post by Doctor.)
reagents are starting to annoy now, just doing questions of Aromatic compounds etc

Organic in CHEM4 is

n.m.r. on the other hand...

[nmudz_009]

Heard that chem 5 is a bitch

[Doctor.]

(Original post by clownfish)
Best advice i can give on reagents is draw a flow chart. One for all the aromatics, and one for the rest of organic. Then label the arrows between each type of compound with the reagents and mechanism needed to get from one to the other.

I did this several times and that helped me get my A.

The problem being, what is there to actually learn In Aromatic
I have read so msny notes that go into too much crap detail. The 'alevelchemistry.co.uk' site is actually more confusing than any good.

Some of the past papers pre new spec just ain't good enough!

(Original post by thegodofgod)
Organic in CHEM4 is

n.m.r. on the other hand...

lol im the otherway, tbh I do love organic. Just a little boring, not bad to get marks though I guess

NMR, I like the carbon one...Hydrogen, little bit odd

[Doctor.]

(Original post by nmudz_009)
Heard that chem 5 is a bitch

Really depends on what your strengths are! CHEM5 is a lot of memory and some advance concepts. Nothing too major though DON'T WORRY

[clownfish]

(Original post by Doctor.)
The problem being, what is there to actually learn In Aromatic (

Print a copy of the syllabus off and this will tell you just what you need to know. page 21 seems to be what you need: http://store.aqa.org.uk/qual/gce/pdf/AQA-2420-W-SP.PDF

[Doctor.]

(Original post by clownfish)
Print a copy of the syllabus off and this will tell you just what you need to know. page 21 seems to be what you need: http://store.aqa.org.uk/qual/gce/pdf/AQA-2420-W-SP.PDF

Already done, just gets a little annoying that so many notes put so much useless crap!

To be honest, I think most of the books over complicate all the NMR stuff! Especially when the specification practically explains what you need to do and learn.

How's everyone else doing?

[Doctor.]

ERGH this is stressing me out now. I don't think I know proton NMR enough, like I can do the questions but they take really long to do.
How's the best way to do it? Many many exam style questions?

Organic synthesis...feel sick

[PatrickD]

I really need to start revising for this, along with CHEM5, soon. We've got a CHEM5 mock soon so I'll probably focus on that for a bit but then I need to knuckle down with all the organic/carbonyl chemistry. We've finished learning CHEM5 and have done the second ISA so I have no excuses now!

As for specific topics, I really like Acids, bases and buffers, Kinetics, and Equilibria (as I can do the calculations without having to remember too much) but all the learning in Compounds containing the carbonyl group, Aromatic chemistry, and Amines is so tedious!