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Author Topic: Edexcel CHEMISTRY DOUBTS!!!!  (Read 268416 times)

Offline guMnam

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #1335 on: June 23, 2011, 09:49:32 am »
and do we need to know the stuff from practicals .. yani the ways toprepare and the colour tests for transition elements ?
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Offline abuelzouz

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #1336 on: June 23, 2011, 09:53:46 am »
yes ofcourse
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Offline Romeesa-Chan

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #1337 on: June 23, 2011, 09:55:04 am »
Quote from: guMnam|The Mask on June 23, 2011, 09:47:50 am
okay.. how does a benzene ring get deactivated ? i mean what groups or what ever deactivatesa benzene ring.. can somebody give me examples ?

That is because one the lone pair of electrons from the oxygen atom on the -OH group interacts with delocalised electrons.

Yes, learn the transition metal test- when we add NaOH and NH3 (+in excess).

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Offline guMnam

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #1338 on: June 23, 2011, 11:05:36 am »
^ so wat do u think happens wen it is deactivated by -NH2 group in phenylamine
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Offline Assi1993

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #1339 on: June 23, 2011, 11:43:16 am »
Guys why doesnt NH4+ act as ligands in formation of complexes?
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Offline abuelzouz

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #1340 on: June 23, 2011, 01:03:15 pm »
info to help:

when co-ordination no of complex is 2
shape is linear
orbitals to be filled sp

when co-ordination no of complex is 4
shape is either square planar
orbitals to be filled dsp^2
or tetrahedral
orbitals to be filled sp^3

when co-ordination no of complex is 6
shape is either octahedral
orbitals to be filled d^2 sp^3
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Offline Romeesa-Chan

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #1341 on: June 23, 2011, 03:27:14 pm »
Quote from: guMnam|The Mask on June 23, 2011, 11:05:36 am
^ so wat do u think happens wen it is deactivated by -NH2 group in phenylamine

^Deactivated by NH2? I am sorry, I don't get it. :/

« Last Edit: June 23, 2011, 03:55:59 pm by Romeesa Chan »
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Offline Assi1993

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #1342 on: June 23, 2011, 03:47:49 pm »
Quote from: Romeesa Chan on June 23, 2011, 03:27:14 pm
^Deactivated by NH2? I am sorry, I don't get it. :/

@Assi1993- NH4+ acts a ligand because it has lone pair of electron present on the Nitrogen atom which forms a covalent bond with the transition metal ion.



noo..why it does NOT form ligandS??
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Offline Romeesa-Chan

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #1343 on: June 23, 2011, 03:55:17 pm »
Quote from: Assi1993 on June 23, 2011, 03:47:49 pm
noo..why it does NOT form ligandS??

WOW. Sorry read it wrong there.  :-[

Complexes are generally formed by donation of a pair of electrons from the ligand to metal; as NH3 with a lone pair on nitrogen can form complex with copper by donating the pair to metal ion. In case of NH4+ the lone pair is not available, so it will not form the complex.

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Offline Assi1993

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #1344 on: June 23, 2011, 04:41:30 pm »
Quote from: Romeesa Chan on June 23, 2011, 03:55:17 pm
WOW. Sorry read it wrong there.  :-[

Complexes are generally formed by donation of a pair of electrons from the ligand to metal; as NH3 with a lone pair on nitrogen can form complex with copper by donating the pair to metal ion. In case of NH4+ the lone pair is not available, so it will not form the complex.



thanks sis :) By the way hows prep?
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Offline Romeesa-Chan

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #1345 on: June 23, 2011, 04:44:36 pm »
Quote from: Assi1993 on June 23, 2011, 04:41:30 pm
thanks sis :) By the way hows prep?


Welcome, sis! <3

Hmmmm, not so great. I am FREAKED OUT. I have to revise Transition Metals properly.

I am gonna do the papers now and let's see.

How's your prep?? (:
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Offline Assi1993

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #1346 on: June 23, 2011, 04:51:04 pm »
ahan..im doing papers..
and im freaking out too...!!
good luck!!!!!!!! :)
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Offline Romeesa-Chan

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #1347 on: June 23, 2011, 04:53:42 pm »
Quote from: Assi1993 on June 23, 2011, 04:51:04 pm
ahan..im doing papers..
and im freaking out too...!!
good luck!!!!!!!! :)

Good luck, dear! <3

Do your best! :D

By the way, how was Unit 4?
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Offline abuelzouz

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #1348 on: June 23, 2011, 06:32:10 pm »
hello..

i just heard of something called CGP revision guide.. Does anybody Have it ?  A link or something? They say its pretty good... ?

Please!
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Offline EMO123

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Re: Edexcel CHEMISTRY DOUBTS!!!!
« Reply #1349 on: June 23, 2011, 06:35:34 pm »
https://studentforums.biz/sciences-149/chemistry-doubts-10366/645/
anybody From Here can you plzz do this the post of mine it is from CIE
if paper needed then ask that for
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