High Stakes
Badges: 16
Rep:
?
#1
Report Thread starter 4 years ago
#1
How are you finding it?

I've been revising organic chemistry and it's so damn long. Been revising acylation for the past hour and the addition-elimination reactions. :rofl:

The kinetics, equilibria and acid/base stuff is a walk in the park because it's GCSE maths though. Tsodsdsihashdaskjdkashdasjhd

RonnieRJ - How good is your memory? How are you gonna pull off A2 Bio and A2 Chemistry without past papers? :rofl: (ofc not hating, your method seems to be working since you did well but it's impressive to the past paper community. )
0
reply
samb1234
Badges: 13
Rep:
?
#2
Report 4 years ago
#2
(Original post by High Stakes)
How are you finding it?

I've been revising organic chemistry and it's so damn long. Been revising acylation for the past hour and the addition-elimination reactions. :rofl:

The kinetics, equilibria and acid/base stuff is a walk in the park because it's GCSE maths though. Tsodsdsihashdaskjdkashdasjhd

RonnieRJ - How good is your memory? How are you gonna pull off A2 Bio and A2 Chemistry without past papers? :rofl: (ofc not hating, your method seems to be working since you did well but it's impressive to the past paper community. )
Too many conditions, colours etc
0
reply
High Stakes
Badges: 16
Rep:
?
#3
Report Thread starter 4 years ago
#3
(Original post by samb1234)
Too many conditions, colours etc
I leave the "memory only and no concept" content for later because I can just sit down and memorise it.
0
reply
Rubato
Badges: 14
Rep:
?
#4
Report 4 years ago
#4
Mechanisms are piss easy. NMR and polymers though are another story...
Also, the mark scheme is so annoyingly specific
Haven't looked at unit 5 yet tbh and don't really want to
1
reply
samb1234
Badges: 13
Rep:
?
#5
Report 4 years ago
#5
(Original post by High Stakes)
I leave the "memory only and no concept" content for later because I can just sit down and memorise it.
Yeah true, it's just insanely dull to have to sit down and learn it. The theory isn't too bad though
0
reply
Applescruff
Badges: 11
Rep:
?
#6
Report 4 years ago
#6
Memorising the mechanisms is alright, you get it after a while.

For me it's proton NMR and 90% of transition metals that are going to ruin me
0
reply
Dinasaurus
Badges: 22
Rep:
?
#7
Report 4 years ago
#7
Idek what acylation is? o.0
0
reply
Rubato
Badges: 14
Rep:
?
#8
Report 4 years ago
#8
(Original post by Dinasaurus)
Idek what acylation is? o.0
It's a nucleophilic addition elimination reaction between an amine and acyl chloride/(acid anhydride?) Acylation is also where you react alcl3 and an acyl chloride to form a reactive intermediate then react it with benzene. Don't call it acylation in the exam though. The mechanism name is the ideal answer.
0
reply
Dinasaurus
Badges: 22
Rep:
?
#9
Report 4 years ago
#9
(Original post by Manexopi)
It's nucleophilic addition elimination where you react alcl3 and an acyl chloride to form a reactive intermediate then react it with benzene. It can also be a reaction between an amine and acyl chloride/(carboxylic acid?) as well. Don't call it acylation in the exam though. Nucleophilic add elim is the ideal answer.
I don't think we do that in OCR then, never come across that.
0
reply
Rubato
Badges: 14
Rep:
?
#10
Report 4 years ago
#10
(Original post by Dinasaurus)
I don't think we do that in OCR then, never come across that.
Yeah, this is AQA spec stuff (: I just realised I made a bunch of chemistry errors in my post as well so will edit
1
reply
High Stakes
Badges: 16
Rep:
?
#11
Report Thread starter 4 years ago
#11
(Original post by Dinasaurus)
Idek what acylation is? o.0
(Original post by Manexopi)
It's nucleophilic addition elimination where you react alcl3 and an acyl chloride to form a reactive intermediate then react it with benzene. It can also be a reaction between an amine and acyl chloride/(acid anhydride?) as well. Don't call it acylation in the exam though. Nucleophilic add elim is the ideal answer.
I think you got aromatic chemistry in there with the benzene.

Acylation is simply adding an acyl group and we do this through introducing nucleophiles (reagents that attack positively charged carbon atoms) to our "acid derivatives" which are (for A-level anyway) Acid Chlorides and Acid Anhydrides. You simply need to learn their reactions with the following nucleophiles:

Ammonia to produce an amide.
Primary amine to produce an N-substituted amide.
Alcohol to produce an Ester.
Water to produce a Carboxylic acid.

In the reactions, all the nucleophiles listed above are initially neutral so they lose a H+ ion (proton), we call this Hydrogen the "active hydrogen".

Oh and you have to remember why we prefer to use Ethanoic Anhydride over Ethanoyl Chloride which is because:

- Cheaper.
- Less corrosive.
- Reacts less readily with water.
- Produces a less harmful byproduct!
1
reply
Amellia123
Badges: 15
Rep:
?
#12
Report 4 years ago
#12
(Original post by Manexopi)
Mechanisms are piss easy. NMR and polymers though are another story...
Also, the mark scheme is so annoyingly specific
Haven't looked at unit 5 yet tbh and don't really want to
I agree, theyre kind of a gift for me on the papers :lol:
Ikr, on the Chem4 2015 paper it asked for the molecular formula of TMS and apparently Si(CH3)4 was wrong (should have been SiC4H12

Unit 5 is quite bad... the ligand substation stuff is hard to remember and autocatalysis drives me insane :rofl:
1
reply
girl :D
Badges: 12
Rep:
?
#13
Report 4 years ago
#13
any one doing or done their Chem isa's because those are what mess every thing up lol
1
reply
Dinasaurus
Badges: 22
Rep:
?
#14
Report 4 years ago
#14
I'm such a fool, I tried to rearrange the Henderson-Hasselbach formula because I remember I was able to simply it but I ended it just simplifying it down to pH=log(1/[H])

Which is the same as the original pH formula in the first place ;_;
2
reply
Rubato
Badges: 14
Rep:
?
#15
Report 4 years ago
#15
(Original post by High Stakes)
I think you got aromatic chemistry in there with the benzene.

Acylation is simply adding an acyl group and we do this through introducing nucleophiles (reagents that attack positively charged carbon atoms) to our "acid derivatives" which are (for A-level anyway) Acid Chlorides and Acid Anhydrides. You simply need to learn their reactions with the following nucleophiles:

Ammonia to produce an amide.
Primary amine to produce an N-substituted amide.
Alcohol to produce an Ester.
Water to produce a Carboxylic acid.

In the reactions, all the nucleophiles listed above are initially neutral so they lose a H+ ion (proton), we call this Hydrogen the "active hydrogen".

Oh and you have to remember why we prefer to use Ethanoic Anhydride over Ethanoyl Chloride which is because:

- Cheaper.
- Less corrosive.
- Reacts less readily with water.
- Produces a less harmful byproduct!
The specification states we do need to know of acylation in aromatic (Friedel-Crafts acylation) Either way, I always refer to these reactions by the name of the mechanism anyways as opposed to acylation e.g nculeophilic addition elimination in the amine related stuff and electrophilic substitution in the aromatic chapter.

Thanks for the info though :3 I did a pack of aromatic and amine questions in one so I'm abit confused rn
0
reply
Rubato
Badges: 14
Rep:
?
#16
Report 4 years ago
#16
(Original post by Amellia123)
I agree, theyre kind of a gift for me on the papers :lol:
Ikr, on the Chem4 2015 paper it asked for the molecular formula of TMS and apparently Si(CH3)4 was wrong (should have been SiC4H12

Unit 5 is quite bad... the ligand substation stuff is hard to remember and autocatalysis drives me insane :rofl:
Ikr. The mark scheme is always the same as well 8)
Wait what? But what you said seems more specific?
Idek what ligand substitution is..or autocatalysis I want to get unit 4 down before I even attempt unit 5. But unit 4 isn't going too well either. I have problems with polymers,amino acids and nmr/mass spec - doesn't help that I find them boring xD Also acid/base calcuations. I'm so confused why some of those titration/buffer calculations require you to take the total volume into account whilst others dont.
0
reply
High Stakes
Badges: 16
Rep:
?
#17
Report Thread starter 4 years ago
#17
(Original post by Manexopi)
Ikr. The mark scheme is always the same as well 8)
Wait what? But what you said seems more specific?
Idek what ligand substitution is..or autocatalysis I want to get unit 4 down before I even attempt unit 5. But unit 4 isn't going too well either. I have problems with polymers,amino acids and nmr/mass spec - doesn't help that I find them boring xD Also acid/base calcuations. I'm so confused why some of those titration/buffer calculations require you to take the total volume into account whilst others dont.
Depends on the volume added. It's all relative. Flick to page 48 in your A2 AQA book and look at the example. It's a change in 1%. Now, you can to be safe, always take into account the new volume...But since you're gonna be rounding up in the end a 1% change in vol won't have much of an affect. Whether you get 2.87 or 2.867
0
reply
Rubato
Badges: 14
Rep:
?
#18
Report 4 years ago
#18
(Original post by High Stakes)
Depends on the volume added. It's all relative. Flick to page 48 in your A2 AQA book and look at the example. It's a change in 1%. Now, you can to be safe, always take into account the new volume...But since you're gonna be rounding up in the end a 1% change in vol won't have much of an affect. Whether you get 2.87 or 2.867
Okay that makes sense. What about the difference in question 2c in this paper? Sorry I'm so rubbish at chemistry
I got a completely different answer to the mark scheme (4.76)
http://filestore.aqa.org.uk/subjects...W-QP-JUN11.PDF
0
reply
thatcooldude2.0
Badges: 15
Rep:
?
#19
Report 4 years ago
#19
Don't know about you guys but I'm loving A2 Chemistry
0
reply
Amellia123
Badges: 15
Rep:
?
#20
Report 4 years ago
#20
(Original post by Manexopi)
Ikr. The mark scheme is always the same as well 8)
Wait what? But what you said seems more specific?
Idek what ligand substitution is..or autocatalysis I want to get unit 4 down before I even attempt unit 5. But unit 4 isn't going too well either. I have problems with polymers,amino acids and nmr/mass spec - doesn't help that I find them boring xD Also acid/base calcuations. I'm so confused why some of those titration/buffer calculations require you to take the total volume into account whilst others dont.
Haha ikr that's why my teach said :lol: but apparently it was the 'molecular' formula
That's a good idea actually - tackling unit 5 when you've aced unit 4 will make revision for the real thing a lot easier
Same, amino acids, polymers and NMR are so boring, to help you I recommend this site (it does OCR and AQA)
http://www.a-levelchemistry.co.uk/

And with bases/bufferes all I can suggest is revise from past paper questions to cover ever style of question.

If there are any questions you would like help with I would be more than willing to help you. Feel free to post them on here or PM/VM me
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

Should there be a new university admissions system that ditches predicted grades?

No, I think predicted grades should still be used to make offers (581)
34.2%
Yes, I like the idea of applying to uni after I received my grades (PQA) (698)
41.08%
Yes, I like the idea of receiving offers only after I receive my grades (PQO) (342)
20.13%
I think there is a better option than the ones suggested (let us know in the thread!) (78)
4.59%

Watched Threads

View All