Chemistry p5 doubts

[LimeReem]

Assalamoalaikum! Hey everyone... since many of us are having doubts , why not make a seperate thread for doubts other than the tips thread....

 

[hassansabir]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w10_qp_53.pdf

question 2(a) i don't get, what do they exactly want us to fill in the table?

 

[Jaf]

I've attached a picture of the table with the values (see expression for how each one was calculated):



The expression I've used is a simplified one where I do not include the conversion of cm3 to dm3 because the conversions eventually get cancelled. To give you a single example expt 1. for conc in water:
moles of NaOH = 0.1 * (24.3/1000) = 2.43 * 10^(-3)
moles of succinic acid = [2.43 * 10^(-3)]/2 = 1.215 * 10^(-3) (since mole ratio NaOH:succinic acid = 2:1; notice the 2 carboxylic acids groups in the formula of succinic acid)
conc. of succinic acid = [1.215 * 10^(-3)]/(10/1000) = 0.1215 mol/dm^3 .... which is essentially what I got in the above table (rounded to 3 sf)

Sorry for the orientation of the image. I can't seem to correct it. You'll have to download it and rotate it yourself.

 

[hassansabir]

thankyou very much

 

[Jaf]

thankyou very much

hassansabir hand-writing nahi pehchani?

 

[xtremeforums]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s10_qp_52.pd
Please answer this, I would be grateful to you!
How do we draw the diagram for question 1c?
And can someone please explain how to make the molal solutions for part 1d?
Instead of dissolving different masses in (the same volume of) water, can we prepare a 1 molal solution, by dissolving 7.46g of the chloride in 100g of water. Then carry out serial dilutions of the 1 molal solution to prepare 0.8, 0.6, 0.4 etc etc molal solutions?
This method is not mentioned in the mark scheme though..
THANKYOU ​

xtremeforums​

 

[hassansabir]

hassansabir hand-writing nahi pehchani?

BASIMMM? :O

 

[saifookhan]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s10_qp_52.pd​

Please answer this, I would be grateful to you!​

How do we draw the diagram for question 1c?​

And can someone please explain how to make the molal solutions for part 1d?​

Instead of dissolving different masses in (the same volume of) water, can we prepare a 1 molal solution, by dissolving 7.46g of the chloride in 100g of water. Then carry out serial dilutions of the 1 molal solution to prepare 0.8, 0.6, 0.4 etc etc molal solutions?​

This method is not mentioned in the mark scheme though..​

THANKYOU ​

xtremeforums

Sorry i dont have much time to type things out.
Pardon me for my crappy writing.

USE PARAFFIN INSTEAD OF DIESEL.

 

[xtremeforums]

Sorry i dont have much time to type things out.
Pardon me for my crappy writing.

USE PARAFFIN INSTEAD OF DIESEL.

Thankyou very much for taking out the time to upload these! And they were of great help

 

[saifookhan]

Thankyou very much for taking out the time to upload these! And they were of great help

Remember me in your prayers.

 

[jojo146]

Hi every one can any body help me in a matter in my cie Alevel exam the question was to draw the structural formula of a isomer instead of structural formula i gave them the displayed formula but all of them were correct so will i get any marks or not its was of 5 marks I am so upset because of this plz guide me !

 

[xtremeforums]

Hi every one can any body help me in a matter in my cie Alevel exam the question was to draw the structural formula of a isomer instead of structural formula i gave them the displayed formula but all of them were correct so will i get any marks or not its was of 5 marks I am so upset because of this plz guide me !

I don't think you would lose any marks at all... as long as the displayed formula was correct. You might have lost some marks if you drew a displayed structure instead of a "skeletal" structure.
Allah knows best. And nothing can be done now anyway. Prepare well for the other papers, and hope for the best.

 

[Jinkglex]

guys in paper 52 MJ 2011 it says measure the opacity and the examiner has only quoted use of marked "X" but i did the experiment in water bath and want to use a colorimeter....would this be wrong and could someone please give me details on how the colorimeter actually works? {Yes i know it measures strength of color }​

secondly in the same paper the columns i labelled amount of water, amount of potassium chlorate and then the latter/former x 100...was this correct?

 

[saifookhan]

guys in paper 52 MJ 2011 it says measure the opacity and the examiner has only quoted use of marked "X" but i did the experiment in water bath and want to use a colorimeter....would this be wrong and could someone please give me details on how the colorimeter actually works? {Yes i know it measures strength of color }​

secondly in the same paper the columns i labelled amount of water, amount of potassium chlorate and then the latter/former x 100...was this correct?

The use of "x" is this that in the conical flash you have all the reactants and you keep it on a paper on which there is a big x.
when the reaction starts, the X gets blurry when seen from above. And once it's completely "opaque", you wont see the X.

 

[Jaf]

BASIMMM? :O

 

[xtremeforums]

Can somebody please clear my confusion in this question??
In O/N 12 p53 Q1aiii) The graph to be sketched is of volume and pressure, and then they ask to sketch the graph if the temperature is increased. In the markscheme, they say that the graph plotted should be parallel to the first one.
And in M/J 12 51 Q2g) they ask to sketch the line if the experiment of Volume x temperature, is repeated with lower pressure.
And in the mark scheme they mention that the line should not be parallel to the original one.

When do we know when it's supposed to be parallel and when it's supposed to be of a different gradient?
Thankyou in advance!

Links to the papers:
http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Chemistry%20(9701)/9701_s12_qp_51.pdf
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w12_qp_53.pdf

 

[railey]

Salaam Alaykum guys,
Hope everyone's good, could someone please show me there diagram of the apparatus drawn on the May/June 2012 paper 52 q1c)? please that would be great.

 

[saifookhan]

Salaam Alaykum guys,
Hope everyone's good, could someone please show me there diagram of the apparatus drawn on the May/June 2012 paper 52 q1c)? please that would be great.

I saw many people are stuck with this particular question.

 

[Resha rimaz]

ppl wat tym is ur ppr. I mean how many hours more?

 

[hassansabir]

I saw many people are stuck with this particular question.

will N2O not dissolve in condensed water?