Paper 5 Tips !! :)

[Ash1994]

are u sure ur asking the right question from the right year? Part 1 d of w08 is not abt the gradient...

Oh sorry 2e the faraday's constant one

 

[knowitall10]

JazakAllah for the reply sis but what to do about this question then ?

I just tagged another sister who had the same doubt this morning... let's see if she got the answer.. otherwise, let's attack our teachers

 

[knowitall10]

Oh sorry 2e the faraday's constant one

1 mol of Cu 2+ = 2 Faradays
63.5g = 2F
1g = 3000C
2F= 63.5 x 3000
F= 95 250 C/mol
Am i clear?

 

[Zari]

I just tagged another sister who had the same doubt this morning... let's see if she got the answer.. otherwise, let's attack our teachers

JazakAllah once again for the reply sis yeh i hope so that sis is able to clear our dbt in sha Allah but if not i will surely take ur advice about attacking the teachers

 

[Gémeaux]

o and oct/nov 2009 Q1) d) how are we supposed to vary the range of concentrations, because whenever i am converting it to the voume of the soltion needed i keep getting volumes exceeding 30 cm^3 and what on earth are we supposed to calculate [diacid] and [monoacid]

For this we fix the volume. I keep it 20cm^3 for each acid. Then depending on whether the acid is monobasic or dibasic, write the conc. i.e., 2.0 mol/dm^3 for monobasic and 1.0 mol/dm^3 for dibasic. Once you've set the conc. and volume, calculate the moles for each separately for the complete experiment (here the question just requires moles and hence mass for ethanedioic acid, so calculate for this and leave the rest).

 

[Ash1994]

1 mol of Cu 2+ = 2 Faradays
63.5g = 2F
1g = 3000C
2F= 63.5 x 3000
F= 95 250 C/mol
Am i clear?

where did you get 1g=3000C from ?

 

[Soldier313]

are you guys doing mass of solid/ mass of solution x 100?

mass of solid/mass of water x 100

 

[iKhaled]

for question 1 d october november 2010 paper 51 how can i prepare 250cm^3 of 0.1M aqueous lead nitrate?
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w10_qp_51.pdf

you know what..i cant do the whole planning for this question arghhh..someone pls help

 

[Soldier313]

Soldier313 thank you SOSOMUCH that was such a great explanation!
I'll pray you get what you want out of these exams In Shaa Allah!!

- one last thing, how do I calculate the weak acids then???

Aww aameen inshaAllah <3 i pray the same for you sis
weak acids, you follow the procedure,
(volume x c x deltatheta ) / moles of water formed
for weak acids, i believe some sort of data must be given inorder fo you to calculate a value. This is as far as I know, unless someone's got another way

All the best!

 

[knowitall10]

where did you get 1g=3000C from ?

The data booklet

 

[knowitall10]

mass of solid/mass of water x 100

Is it the same thing? i forgot the year we were discussing

 

[Zari]

Is it the same thing? i forgot the year we were discussing

i guess M/J 09 Q2 a

 

[knowitall10]

i guess M/J 09 Q2 a

Oh yea, Jazaki Allah
umm, i uploaded a photo a few pages back Soldier313 u might wanna take a look at my table

 

[knowitall10]

Oh yea, Jazaki Allah
umm, i uploaded a photo a few pages back Soldier313 u might wanna take a look at my table

and u Zari

 

[biba]

anyone please help me with this:
in a few qs such as JUNE/11/52 it is clearly stated that we have to draw a LINE OF BEST FIT but in the mark scheme it is written that NO MARKS FOR A STRAIGHT LINE ! EXAMINER'S JUDGEMENT ON THE BEST-FIT CURVES !

 

[knowitall10]

anyone please help me with this:
in a few qs such as JUNE/11/52 it is clearly stated that we have to draw a LINE OF BEST FIT but in the mark scheme it is written that NO MARKS FOR A STRAIGHT LINE ! EXAMINER'S JUDGEMENT ON THE BEST-FIT CURVES !

So what do u learn? That when the questions says line of best fit, it can also be a curve of best fit no?

 

[leosco1995]

A line of best fit can also be a curve.

 

[biba]

So what do u learn? That when the questions says line of best fit, it can also be a curve of best fit no?

um but how do we decide?

 

[mahmuda akter]

can u please help me about oct/nov10/53 1(c)? what apparatus to use?

 

[iFuz]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w12_qp_53.pdf
Question 3 last 2 parts :|