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Chemistry Paper 4-theory- doubts =D

knowitall10

knowitall10

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Assalamu Alaykum AS and A2!
i just figured out that our Chemistry textbook had some errors:eek:
So, i would like you to follow this link and make sure you read the whole page because it is very important. I'm very sorry for the AS fellows because they had their paper 2 long ago.. but maybe u can do p4 and p5 better next year :) Good Luck!
As for A2, the thought of only getting to know this a week b4 our p4 is very scary. With all due honesty, I have absolutely no words to calm you down as i myself am suffering from a "close-to-a-heart-attack" stage....
http://www.chemguide.co.uk/CIE/ciebook.html
Good Luck.....................................inshAllah Allah will Help!!!!!!!!!
 
abcde

abcde

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Xtremite said:
Hi guys again,

So here's my question. It's related to mass spectra.

Question 2, part (c) of this paper: http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s07_qp_4.pdf

Mark scheme: http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s07_qp_4.pdf

The examiner report states: Many candidates seem not to have been taught this new section of the Core syllabus, namely the
interpretation of mass spectra in terms of molecular fragments.

How do I do this?
Click to expand...

There isn't much to this question other than trying to figure out how you could use atoms/elements in the original compound (ammonium nitrate) to make fragments that would add up to each of the peaks in the question. My initial hunch was that A and B would be NH3 and NO2, but those don't balance (I mean even if only one mole of these gases is made, the Mr of NH4NO3 - 62 - is not equal to the combined Mr of both product gases - 17 + 46 = 63, so this must be dismissed.) Instead, chose two gases that would separately make up the maximum m/e values, 18 and 44 using onlu the elements provided. These would be H2O (18) and N2O (44). They even balance! 18 + 44 = 62. Then you can break these up to make each of the smaller values: O+ = 16, OH+ = 17. And N+ = 14, O+ = 16, N2+ = 28, NO+ = 30. (They'll all have positive signs 'cause the spectrometer only deals with positive ions.)
 
railey

railey

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knowitall10 said:
Assalamu Alaykum AS and A2!
i just figured out that our Chemistry textbook had some errors:eek:
So, i would like you to follow this link and make sure you read the whole page because it is very important. I'm very sorry for the AS fellows because they had their paper 2 long ago.. but maybe u can do p4 and p5 better next year :) Good Luck!
As for A2, the thought of only getting to know this a week b4 our p4 is very scary. With all due honesty, I have absolutely no words to calm you down as i myself am suffering from a "close-to-a-heart-attack" stage....
http://www.chemguide.co.uk/CIE/ciebook.html
Good Luck.....................................inshAllah Allah will Help!!!!!!!!!
Click to expand...
Just use chemguide.co.uk/cie to revise from. ;)
 
S

safaXXX

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Hellooo,
I wanted to ask how do u guys study for the applications, like what is the most important topics? :p
 
knowitall10

knowitall10

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ASSLAMU ALAYKUM WA RA7MATULLAH!!!

NOTE: THE CHEMISTRY APPLICATIONS BOOKLET SUCKS BIG TIME AND HAS BEEN PROVEN SO BY THE CHEM GUIDE SITE. PLEASE REFER TO THAT SITE FOR THE LAST FEW CHAPTERS AFTER ORGANIC BECAUSE IT IS PRECISELY TO THE POINT AND ACCORDING THE CURRENT SYLLABUS. THE MORE MISTAKES THE GUY POINTS OUT, THE CLOSER I GET TO HAVING A STROKE. IT'S VERY IMPORTANT!!!
Thank you.
May Allah Help us lead the path of Righteousness:)
 
knowitall10

knowitall10

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safaXXX said:
Hellooo,
I wanted to ask how do u guys study for the applications, like what is the most important topics? :p
Click to expand...
Sister, if ur a biology student, then forget the chem of life chapter except the weirdo bonding at the start. Focus mainly on Applications of Analytical Chem and Design and Materials.
 
knowitall10

knowitall10

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and safaXXX for God's Sake do not even touch the chemistry applications booklet. the number of errors i just read about are literally humongous and I strongly suggest u stick to the Chem Guide site. It's the perfect site, i wish i had known about it earlier. Well, no regrets only lessons:p, so yeah, i hope i helped u:)
 
Zari

Zari

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knowitall10 said:
ASSLAMU ALAYKUM WA RA7MATULLAH!!!

NOTE: THE CHEMISTRY APPLICATIONS BOOKLET SUCKS BIG TIME AND HAS BEEN PROVEN SO BY THE CHEM GUIDE SITE. PLEASE REFER TO THAT SITE FOR THE LAST FEW CHAPTERS AFTER ORGANIC BECAUSE IT IS PRECISELY TO THE POINT AND ACCORDING THE CURRENT SYLLABUS. THE MORE MISTAKES THE GUY POINTS OUT, THE CLOSER I GET TO HAVING A STROKE. IT'S VERY IMPORTANT!!!
Thank you.
May Allah Help us lead the path of Righteousness:)
Click to expand...
Jazakillah sis :)
 
S

SexyFag

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Guys can i get some solid notes for Organic chemistry for A2? Paper 4 is really tough for me, And i know majority of it is Organic, So I want to prepare myself for Organic to score majority of the marks... So something i can go through that will allow me to answer all organic questions? :)
 
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SexyFag

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knowitall10

knowitall10

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SexyFag said:
The first link is for AS, so no use, and the second link was a little useful, but no solid organic chem in that
Need some solid stuff that will help me answer teh paper 4 organic questions :)
Click to expand...
I recommend chem guide.. have u tried it?
 
iKhaled

iKhaled

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Zari said:
Asalamualikum :) i have a dbt in paper O/N 10 variant 41 Q4 part c (ii) http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w10_qp_41.pdf from where did 4 come in ksp shouldnt it be just x^3 :cautious: ?
Click to expand...
hey and no u r mistaken the equation is

pbcl2 --> pb^2+ + 2cl^- the ksp = [pb^2+][Cl-]^2 now u see when pbcl2 dissolves u will have x concentration of pb^2+ AND 2x of cl^-1 not x too because the ratio is 1:2 so
ksp = x(2x)^2
ksp = 4x^3 i hope u got it!
 
Zari

Zari

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iKhaled said:
hey and no u r mistaken the equation is

pbcl2 --> pb^2+ + 2cl^- the ksp = [pb^2+][Cl-]^2 now u see when pbcl2 dissolves u will have x concentration of pb^2+ AND 2x of cl^-1 not x too because the ratio is 1:2 so
ksp = x(2x)^2
ksp = 4x^3 i hope u got it!
Click to expand...
JazakAllah bro :) got it :D btw i guess u made a mistake in the ksp equation it is actually ksp=[Pb^2+][Cl-]^2
 
littlecloud11

littlecloud11

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SexyFag said:
Guys can i get some solid notes for Organic chemistry for A2? Paper 4 is really tough for me, And i know majority of it is Organic, So I want to prepare myself for Organic to score majority of the marks... So something i can go through that will allow me to answer all organic questions? :)
Click to expand...

Here's my note for Organic. The handwriting is way off so apologies for that.
I can't seem to upload the file here. :(
You can download the pdf from here-
http://www.convert-jpg-to-pdf.net/result.php
 
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