OCR F324-June 2013 Chemistry

Original post by ZakRob

State two reasons why the diazotisation reaction where Nitrous acid is formed insitu is carried out at 10 degrees or less

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1) Is it because it exceeds activation energy as partiles gain K.E for reaction to proceed

2) In order to form nitrous acid, the HCL and HNO2 have to react at a lesser temperature because you are making an acid and takes place at lower temp.In-situ , steam HCL is reacted and therefore has to be in an open system and it releases fume

Reply 562

Original post by otrivine

My two reasons in mind are: nitrous acid is explosive so it's safer to operate at lower temperatures. And the Di-azonium salt breaks down at high temperatures so low temp to maintain the salt

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(edited 11 years ago)

Reply 563

Original post by ZakRob

aRE these mark schemes answer? or you are making them? if so very nice questions.

Ok

Define:isoelectric point

Reply 564

Original post by otrivine

aRE these mark schemes answer? or you are making them? if so very nice questions.

Ok

Define:isoelectric point

Making them up, but im trying to make questions which are less common.

The isoelectric point is a pH at which an amino acid forms a zwitterion.
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Reply 565

Original post by ZakRob

Making them up, but im trying to make questions which are less common.

The isoelectric point is a pH at which an amino acid forms a zwitterion.
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yup, do you reckon my points are reasonable?

my turn

Reply 566

Original post by otrivine

yup, do you reckon my points are reasonable?

my turn

Yes, what are the conditions and reagents required for the reduction of aldehydes and ketones?

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Reply 567

Original post by ZakRob

Yes, what are the conditions and reagents required for the reduction of aldehydes and ketones?

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reagents= aq NaBH4
conditions= heat

Reply 568

Original post by otrivine

reagents= aq NaBH4
conditions= heat

Correct

i'm finished for today

Reply 569

NMR Test 10 Mark Scheme.pdf438.6KB

Original post by ZakRob

Correct

i'm finished for today

OK, it was nice revising with you :smile:

Reply 570

kimsiclez

For anyone struggling with NMR here are some useful resources:

http://www.youtube.com/watch?v=k6F__pysc74

http://www.youtube.com/watch?v=5JJ5IAlQYZs

These are both great videos for explaining NMR and how to tackle those high mark questions - I found them really useful at least.

I know there aren't a lot of resources out there for proton and carbon NMR in terms of practice so have attached a few files on stuff we were given in school in case anyone is interested.

Good Luck everyone!

C13 NMR Q.pdf129.1KB

NMR Worksheet.pdf438.5KB

NMR Test 10.pdf448.8KB

Reply 571

Original post by otrivine

OK, it was nice revising with you :smile:

When will you finish learning all the modules for F324?

Reply 572

Original post by MasterYi

When will you finish learning all the modules for F324?

I finished learning, now I am revising ? you?

Reply 573

Original post by otrivine

I finished learning, now I am revising ? you?

Great that means you'll able to answer the analysis question. :smile:

I've finished too, just revising now.

Reply 574

Original post by MasterYi

Great that means you're able to any the analysis question. :smile:

I've finished too, just revsing now.

Yes, I did proton NMR! On thursday I am going to revise carbon 13 and next week finish off chromatography, then start past papers and do plenty of questions!

By the way up for some recap revision :wink:

Reply 575

Better

Original post by otrivine

Start Past Papers.....I really need to finish Chem 4 Mod 1/2 by the end of his week :O

Reply 576

Original post by otrivine

Great, how does one revise module 3. Like the chromotography and NMR data.
What's the extent of the recap revision?

Reply 577

Original post by MasterYi

Great, how does one revise module 3. Like the chromotography and NMR data.
What's the extent of the recap revision?

Doing all the questions at the back of the book :smile:

Want to revise

Reply 578