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Author Topic: ALL CIE CHEMISTRY DOUBTS HERE !!  (Read 119159 times)

Offline Arthur Bon Zavi

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Re: ALL CIE CHEMISTRY DOUBTS HERE !!
« Reply #435 on: April 15, 2011, 03:45:09 pm »
Ignored the hydrolysis part. ::)
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elemis

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Re: ALL CIE CHEMISTRY DOUBTS HERE !!
« Reply #436 on: April 15, 2011, 04:23:44 pm »
Quote from: Fidato on April 15, 2011, 03:45:09 pm
Ignored the hydrolysis part. ::)

Hmm ?
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Offline Arthur Bon Zavi

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Re: ALL CIE CHEMISTRY DOUBTS HERE !!
« Reply #437 on: April 15, 2011, 04:30:33 pm »
Quote from: Ari Ben Canaan on April 15, 2011, 04:23:44 pm
Hmm ?

The previous question which you answered. So was getting false difference. Thanks though.
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elemis

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Re: ALL CIE CHEMISTRY DOUBTS HERE !!
« Reply #438 on: April 15, 2011, 04:41:02 pm »
Quote from: Fidato on April 15, 2011, 04:30:33 pm
The previous question which you answered. So was getting false difference. Thanks though.

You mean Master_key forgot about the hydrolysis ?
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Offline Arthur Bon Zavi

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Re: ALL CIE CHEMISTRY DOUBTS HERE !!
« Reply #439 on: April 15, 2011, 04:54:11 pm »
Quote from: Ari Ben Canaan on April 15, 2011, 04:41:02 pm
You mean Master_key forgot about the hydrolysis ?

We both were solving in the class.
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Offline Master_Key

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Re: ALL CIE CHEMISTRY DOUBTS HERE !!
« Reply #440 on: April 16, 2011, 01:47:15 pm »
Got it.

CH3CHO + HCN ---> CH3CHOCN

CH3CHOCN + H2O ---> CH3CHOHCOOH (RFM=90).
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Offline TJ-56

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Re: ALL CIE CHEMISTRY DOUBTS HERE !!
« Reply #441 on: April 18, 2011, 01:08:11 pm »
Hey.
Can someone help me with the following Paper 4 questions?
May/June 2002 Question 3 (c) (ii)
May/June 2003 Questions 2 (b) (iii) & 3 (b) (i) & (c)
Any help is greatly appreciatied, thanx in advance!
« Last Edit: April 18, 2011, 02:07:46 pm by TJ-56 »
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Offline EMO123

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Re: ALL CIE CHEMISTRY DOUBTS HERE !!
« Reply #442 on: April 18, 2011, 01:30:07 pm »
Quote from: TJ-56 on April 18, 2011, 01:08:11 pm
Hey.
Can someone help me with the following:
May/June 2002 Question 3 (c) (ii)
May/June 2003 Questions 2 (b) (iii) & 3 (b) (i) & (c)
Any help is greatly appreciatied, thanx in advance!
but which paper?
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Offline TJ-56

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Re: ALL CIE CHEMISTRY DOUBTS HERE !!
« Reply #443 on: April 18, 2011, 02:08:29 pm »
Quote from: EMO123 on April 18, 2011, 01:30:07 pm
but which paper?


Sorry, didnt notice, Paper 4.
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Offline EMO123

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Re: ALL CIE CHEMISTRY DOUBTS HERE !!
« Reply #444 on: April 18, 2011, 02:29:26 pm »
3(b)(i)

CO2 + 2NaOH ? Na2CO3 + H2O

SnO2 + 2NaOH ? Na2SnO3 + H2O

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Offline TJ-56

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Re: ALL CIE CHEMISTRY DOUBTS HERE !!
« Reply #445 on: April 18, 2011, 03:45:18 pm »
Quote from: EMO123 on April 18, 2011, 02:29:26 pm
3(b)(i)

CO2 + 2NaOH ? Na2CO3 + H2O

SnO2 + 2NaOH ? Na2SnO3 + H2O



Thanx.
Regarding the third reaction though, SiO2, silicon (iv) dioxide, on the markscheme gives a similar reaction to that of SnO2, but I have read that SiO2 and NaOH dont react. So i dont know if the book is incorrect or the mark scheme. Do they react?
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elemis

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Re: ALL CIE CHEMISTRY DOUBTS HERE !!
« Reply #446 on: April 18, 2011, 04:21:43 pm »
Quote from: TJ-56 on April 18, 2011, 03:45:18 pm
Thanx.
Regarding the third reaction though, SiO2, silicon (iv) dioxide, on the markscheme gives a similar reaction to that of SnO2, but I have read that SiO2 and NaOH dont react. So i dont know if the book is incorrect or the mark scheme. Do they react?

It does react. You would get Na2SiO3 and water

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Offline TJ-56

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Re: ALL CIE CHEMISTRY DOUBTS HERE !!
« Reply #447 on: April 18, 2011, 05:41:36 pm »
Quote from: Ari Ben Canaan on April 18, 2011, 04:21:43 pm
It does react. You would get Na2SiO3 and water



oh ok thanx
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Offline EMO123

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Re: ALL CIE CHEMISTRY DOUBTS HERE !!
« Reply #448 on: April 19, 2011, 12:48:07 pm »
Quote from: TJ-56 on April 18, 2011, 05:41:36 pm
oh ok thanx
by mistake i wrote it Na2SnO3
it is written right by ari
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Offline thecandydoll

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Re: ALL CIE CHEMISTRY DOUBTS HERE !!
« Reply #449 on: April 19, 2011, 02:17:33 pm »
A few of the organic questions in A2 Paper 4 are in the form of skeletal forumla.How do you do it?
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