Chemistry: Post your doubts here!

[Igcse stuff]

once you solve the past pprs from 2004-2012 then u can easily score 30-36 marks easily in that ....
P1 P2 P4 ...score max marks then u can easily get an A*

Thank you very much! .....by the what should I do to get full marks in P2 P3 P4 and P5

 

[Sadia Jahan Lisa]

Assalamualaikum.
How are you all? I need a help. I am a AS student. I will sit for AS examination in coming May-June. I need only the numerical values or practical reading for past practical question papers of chemistry & physics, so that I can do the further tasks of those practical question papers. Can anyone help me please?

 

[Sadia Jahan Lisa]

I need a help. Is there anyone who can help me?

 

[ZaqZainab]

I need a help. Is there anyone who can help me?

Help with?

 

[Sadia Jahan Lisa]

I am a AS student. I need the experimental reading of past year question paper for chemistry practical so that I can do the further calculations. Can anyone help? Please please please

 

[Abdel Moniem]

River water in a chalky agricultural area may contain Ca2+, Mg2+, − 2
3
CO , −
3
HCO , Cl
− and −
3
NO
ions. In a waterworks, such water is treated by adding a calculated quantity of calcium hydroxide.
What will be precipitated following the addition of calcium hydroxide?
A CaCl2
B CaCO3
C Ca(NO3) 2
D Mg(NO3)2

 

[Abdel Moniem]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s11_qp_13.pdf
question 16 and 17

 

[ahmed abdulla]

Assalamualaikum.
How are you all? I need a help. I am a AS student. I will sit for AS examination in coming May-June. I need only the numerical values or practical reading for past practical question papers of chemistry & physics, so that I can do the further tasks of those practical question papers. Can anyone help me please?

For chem its mostly .. c1v1 = c2v2 .. or c=n/v and mole= mass/mr .... Q=mCt
For phy v=Ir .. and rest will be said in the question

 

[Suchal Riaz]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s11_qp_13.pdf
question 16 and 17

As it can be seen X- was oxidised to X2 so it worked as a reducing agent. x- reacted with two other oxidising agents, Y- did with nine and Z- reacted with only one. So X- is strongest and Y- is weakest.
For seventeen, it can be seen that the oxidation only occurs when sulphuric acid reacts with sodium iodide. In all other casses, the products have the same oxidation states. The acidic gas formed was HCl.
Iodine gas has zero state while iodide had -1. Purple color shows that iodine was released.
Therefore, it can be deduced that H2SO4 is stronger oxidising agent than iodine.

 

[Suchal Riaz]

I am a AS student. I need the experimental reading of past year question paper for chemistry practical so that I can do the further calculations. Can anyone help? Please please please

Do atp of o level. It has the reading and all u need to do is to draw graph or do working.

 

[MiniSacBall]

I finished my Chemistry in 20 DAYS..!!! still Getting about 30/60 (paper-2)
Getting WORRIED!

Same here! Chemistry AS is a nightmare!. I am trying to gain control over it. I have finished the course too, but Past Papers are worst night mare, i have ever had!

 

[Hassan Ali Abid]

Thank you very much! .....by the what should I do to get full marks in P2 P3 P4 and P5

Its not that difficult to score good marks in atleast P2 and P4 ...... For this you should be knowing each and everything thing of the syllabus on the fingre tips , concepts should be clear ...and then revising the stuff on regular intervals to ensure that u have retained all what u have prepared ...and then attempting past pprs (*the way u solve the ppr also counts a lot )and then finally discussing the things/doubts and all that with your teacher ...All these things will surely be contributing to get good marks and its very possible to get even full marks and in this way then u wont be having that much tension for either P3 or P5 and easily you can score A*.
P.s even if you get C's or D's in P3 or P5 and very high A grades in P1,2,4 even then you can get an overall A* .

 

[Hassan Ali Abid]

Same here! Chemistry AS is a nightmare!. I am trying to gain control over it. I have finished the course too, but Past Papers are worst night mare, i have ever had!

As chem is a piece of cake ...If u are getting low marks in the P2 ..thats just bcz you haven't prepared the course well ...once you are done with the course only then pick up the pprs and you'll see that getting 55+ is not a big task .

 

[scouserlfc]

Same here! Chemistry AS is a nightmare!. I am trying to gain control over it. I have finished the course too, but Past Papers are worst night mare, i have ever had!

Concentrate on what the person above said. Plus also dont make this assumption of chem being nightmare a reality just think about it as the easiest subject or whatever and try to motivate yourself when doing it because if you dont do it then you will never get over this chemistry nightmare thing and will continue to suffer and in the end u will give up all hope.
So get the syllabus and books and start going through the course again and try to understand whats going on instead of learning everything. Plus if u can do then try for all AS topics the MCQs of very old papers of 80s and 90s they are a wonderful source of building concepts but do the MCQs for each topic on syllabus after u read it. I did this all and then in last month before exam i did past papers and had no problem ALHUMDULILLAH. But im not here to boast but to share my experience so it helps you
By the way cheer up dont be sad as your smilie above shows

 

[Hassan Ali Abid]

Same here! Chemistry AS is a nightmare!. I am trying to gain control over it. I have finished the course too, but Past Papers are worst night mare, i have ever had!

And bro ...prepare the AS chem in parts ..like first u should prepare physical part then inorganic and then organic ...and do highlight the book according to the syllabus ..i mean only imp things ......It will take ..like 4-5 days and once u do it ....u will be so calm at the time revision and dont make the things panic .... InshaAllah it will get easy for you but just give a try .. i hope you understand.

 

[Unknown Killer]

@

Resonable answer
another mark scheme answer which confuse me is :

conditions for changing methylbenzene to chloro methyl benzene as we know is : Uv light and reagent Cl2
but as the markscheme for mj2007 says , it should be Cl2 and hf ! >> whats hf hhh

hf is energy of Photon
Photon is in Light , Ultraviolet Rays ...i.e in Sun Light
So it means , Cl2 with Sun light

 

[yousef]

Chemistry paper 5 ,
Is my scaling right? will i get marks for this..
actually my graph completed more than half of grid but i took a part of pic to zoom the scaling .

 

[1357911]

Chemistry paper 5 ,
Is my scaling right? will i get marks for this..
actually my graph completed more than half of grid but i took a part of pic to zoom the scaling .

The scaling on the y axis is wrong . they should cover more than one half of the graph?? Is it even a half? plus better to start the graph from zero. dont break the graph fom the y axis.

 

[yousef]

The scaling on the y axis is wrong . they should cover more than one half of the graph?? Is it even a half? plus better to start the graph from zero. dont break the graph fom the y axis.

i used more than half of y-axis as well, but to show scaling i took a close pic .
and if we start from 0 , values wouldnt be enough

 

[1357911]

i used more than half of y-axis as well, but to show scaling i took a close pic .
and if we start from 0 , values wouldnt be enough

for the question u did, i think u can.. if the range is too big then u have to take larger values for a particular no. of blocks. If possible send me the link to the question please. Ill try it and show it to you.