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OCR A Chemistry F324 Rings, Polymers and Analysis Thu 26 Jan 2012

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Reply 940
Avatar for Yarpie
Yarpie
9
Original post by Hattie.s
surely it would be the other way round because COOH is acidic therefore bringing it below ph3 and NH2 is a base therefore bringing the ph up?


This is what I thought. I put pH 3 is COOH and pH10 is NH2. Putting a base on would mean that the isoelectric point would need to be higher and putting an acid on would mean the isoelectric point would be lower.
Reply 941
Avatar for 079
079
i drew curly arrow from benzene ring to delta positive carbon then to the oxygen

next one it had H and so3 sticking out, so arrow from h bond going into ring (which has that partially open ring with +)
Reply 942
Avatar for Crabbiey
Crabbiey
Original post by holahola
What was the answer for br2 ?


I put the two bromines on the second and sixth carbons of the benzene ring.
Reply 943
Avatar for Zoe_mj
Zoe_mj
Original post by fudgesundae
Was the intermediate not step 2?

I thought I saw a step 3 lol, oh well.


Hmm I only saw step 1 and step 2 :smile:

Also it was 5 marks, 2 for curly arrows in 1st part, 1 for curly arrow and 1 for intermediate in 2nd part, 1 for arrow in last part :smile:
Original post by holahola
What was the answer for br2 ?


I had it substituted on all 4 available spots on benzene, but I don't think there's a definite answer, I guess they just want you do get that it substituted onto the benzene ring, whether you had 1, 2, 3, or 4 probably doesn't matter.
What would losing 15 marks get me :frown:
Reply 946
Avatar for 079
079
for the br2 on the phenol ring did we have to add to only 2 positions? cause the third one was blocked by N!
When it asked to add Br2 to the the polymer with phenol, what did everyone draw?

I drew it with two bromines at positions 2 and 6 (relative to the OH)
Original post by Zoe_mj
Hmm I only saw step 1 and step 2 :smile:

Also it was 5 marks, 2 for curly arrows in 1st part, 1 for curly arrow and 1 for intermediate in 2nd part, 1 for arrow in last part :smile:


oh Im confused now, I'm sure it was 4 lol?
Reply 949
Avatar for 079
079
Original post by shooby_doo
What would losing 15 marks get me :frown:


foreal..an A!!! :biggrin:
Original post by shooby_doo
What would losing 15 marks get me :frown:


45 out of 60
Reply 951
Avatar for rogersnm
rogersnm
4
Original post by Yarpie
This is what I thought. I put pH 3 is COOH and pH10 is NH2. Putting a base on would mean that the isoelectric point would need to be higher and putting an acid on would mean the isoelectric point would be lower.


I did the reverse, but I haven't got a clue which is right. I would've thought that having the extra NH2 there would take an additional proton therefore requiring a lower pH for the zwitterion to form.
Original post by Yarpie
This is what I thought. I put pH 3 is COOH and pH10 is NH2. Putting a base on would mean that the isoelectric point would need to be higher and putting an acid on would mean the isoelectric point would be lower.


Yes but arent you reversing it to keep it a zwitter ion? :s-smilie:
IDK im talking ****
(edited 12 years ago)
Original post by PeterStoba
45 out of 60


Oh thanks
I thought it was 44
Reply 954
Avatar for Zoe_mj
Zoe_mj
Original post by fudgesundae
oh Im confused now, I'm sure it was 4 lol?


Im pretty sure it was 5, its why I looked for an extra reason to get a mark... :smile:
Reply 955
Avatar for 079
079
Original post by Zoe_mj
Hmm I only saw step 1 and step 2 :smile:

Also it was 5 marks, 2 for curly arrows in 1st part, 1 for curly arrow and 1 for intermediate in 2nd part, 1 for arrow in last part :smile:


arrow in last part? :confused:
Reply 956
Avatar for jlroper5
jlroper5
The 3 steps for making the chlorobenzylamine thingy?
What it 1) Nitrobenzene using H2SO4 and HNO3
2) chloronitrobenzene using Cl2 and ALCL3
3) Reducing the N03 to NH2 using Sn and conc HCL???

Anyone else get this?
Reply 957
Avatar for rogersnm
rogersnm
4
Original post by Zoe_mj
Hmm I only saw step 1 and step 2 :smile:

Also it was 5 marks, 2 for curly arrows in 1st part, 1 for curly arrow and 1 for intermediate in 2nd part, 1 for arrow in last part :smile:


I'm pretty sure it was 4 marks.

Original post by fudgesundae
When it asked to add Br2 to the the polymer with phenol, what did everyone draw?

I drew it with two bromines at positions 2 and 6 (relative to the OH)


Yep, 2 and 6.

Original post by shooby_doo
What would losing 15 marks get me :frown:


Pretty close tp the A/B border, an A in june 11 was 44/60 but we had 15 minutes extra time (with no additional questions).
Reply 958
Avatar for Yarpie
Yarpie
9
Original post by rogersnm
I did the reverse, but I haven't got a clue which is right. I would've thought that having the extra NH2 there would take an additional proton therefore requiring a lower pH for the zwitterion to form.


Ah well. Only time will tell. I hate waiting for the results, that is worse than actually doing the exams.
Reply 959
Avatar for gibb
gibb
I didnt calculate the empirical formula for the last question, I just multiplied the mass of 144 by the percentage of the element.

Do you think this will lose me marks?

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