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F334 (19/06/2013 9:00AM) - Salters Chemistry (Chemistry of Materials) Revision Thread

I wouldn't have thought so, but I guessed that bit :L

Indeed it doesn't deprotonate: http://www.ebi.ac.uk/chebi/searchId.do?chebiId=CHEBI:58570

Does this mean that it was neutral?

Reply 341

Khanzi

6

Absolutely beautiful paper. Got 1.69 for calculation, and 0.0867 s-1 for other one at end, really easy paper compared to January... January I heard the grade boundaries jumped so high because the exam
Boards were under pressure from
The government or something? You can see a trend with most exams having wayyy higher boundaries... I mean I got
64 raw in January and got 63 ums only... So stupid should have got an A

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Reply 342

hannah1994

7

What did people put for

-If the zwitterion was neutral/acidic/alkali?

-The cis/trans isomerism?

Reply 343

Futuristicmedic

1

What are we predicting for an A?

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Reply 344

hannah1994

7

Original post by Futuristicmedic

What are we predicting for an A?

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I'd say same as jan 13, i don't really think it was any easier to be honest

Reply 345

Futuristicmedic

1

Original post by hannah1994

I'd say same as jan 13, i don't really think it was any easier to be honest

Would it not be slightly lower due to the calibre of students taking the test ? My school only does June exams , but at other schools only those retaking will be doing this paper

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Reply 346

ElChapo

18

Original post by EdwinLo

Heat under reflux with acidified potassium dichromate and distil off in situ as the reaction progresses.

Heat under reflux and distil is a con, you cant do both, you just had to say distil.
Marks:
Acidified (1)
Dichromate (1)
Distil (1)

Reply 347

Katie-S

Original post by hannah1994

What did people put for

-If the zwitterion was neutral/acidic/alkali?

-The cis/trans isomerism?

I said it would be acidic as the phenol group donates extra protons.

Then for the cis/trans, I said the ring structure restricted rotation (like the c=c bond would in other e/z molecules) which allowed the amine groups to be on the same or opposite sides

I'm hoping these are correct but don't hold me to it if I'm wrong! :smile:

Reply 348

EdwinLo

Original post by ElChapo

Heat under reflux and distil is a con, you cant do both, you just had to say distil.
Marks:
Acidified (1)
Dichromate (1)
Distil (1)

Wasn't the question something like what are the conditions to oxidise an alcohol, and how could he make sure that only the aldehyde was produced or something? Or what was it?

Reply 349

ElChapo

18

Original post by EdwinLo

Wasn't the question something like what are the conditions to oxidise an alcohol, and how could he make sure that only the aldehyde was produced or something? Or what was it?

Yeah it wanted the reagent(s) and conditions to make sure you formed an aldehyde, and thats to distil it, refluxing would give you a carboxylic acid

Reply 350

EdwinLo

Original post by ElChapo

Yeah it wanted the reagent(s) and conditions to make sure you formed an aldehyde, and thats to distil it, refluxing would give you a carboxylic acid

Damn that sucks I always thought you could "reflux and distil off the product" and my teachers never corrected me...So do you think that would lose 1 mark then? Would I get the other 2 for acidified potassium dichromate?

Reply 351

Mattywooda

Original post by Pandora's Box

Does this mean that it was neutral?

Google is your friend. Quick search shows tyrosine neutral and polar (http://www.elmhurst.edu/~chm/vchembook/561aminostructure.html).

Reply 352

ElChapo

18

Original post by EdwinLo

Damn that sucks I always thought you could "reflux and distil off the product" and my teachers never corrected me...So do you think that would lose 1 mark then? Would I get the other 2 for acidified potassium dichromate?

Yes you should do, only 1 mark though

Reply 353

DoeADeer

9

Is there an unofficial mark scheme?

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Reply 354

super121

5

What did people put for that rate question with the graph?

Reply 355

EdwinLo

Original post by ElChapo

Yes you should do, only 1 mark though

Only 1 mark lost or only 1 mark gained?

Reply 356

Mangodepo11

8

Original post by Mattywooda

Google is your friend. Quick search shows tyrosine neutral and polar (http://www.elmhurst.edu/~chm/vchembook/561aminostructure.html).

I love, so it was definatly neutral? :smile:

Original post by EdwinLo

Damn that sucks I always thought you could "reflux and distil off the product" and my teachers never corrected me...So do you think that would lose 1 mark then? Would I get the other 2 for acidified potassium dichromate?