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Paper 5 Tips !! :)

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Can somebody pls tell me how to do serial dilutions question and how to find concentration. Plz plz plz plz plz
 
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cuco3 on the x axis and mass lost on y axis.... sry for llate reply.... :/
ohh since ur axis is diff frm mine, im nt rely sure hw to do it. bt fr my graph ths is hw i gt it...my x axis ws mass of carbonate n y- mass of CuO
so u gt a point in da graph n read its values ... mine were x-4.4 y-3.05
frst find the moles of CuO. (mr=79.5) do divide 3.05/79.5= 0.038
consider ratio of CuO : CuCo3
2 :1
so 0.038---> x
find x. i.e 0.038/2=0.0192 of mols of carbonate. usin ths fnd the mr of the crbonate i.e. mols=mass/mr, calculated value will b 229.4
nw to fnd da mr of the CuCO3.Cu(OH)2.xH2O, mr of ths= 221+18x
221+18x=229.4
x=0.46 whch is appro=0.5

i knw its a mess, bt hope u gt it sumhw..i rely dnt knw hw to do fr ur graph!
 
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Can somebody pls explain me serial dilution making and concentration related question. Vl b very thankful. Plzz
 
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Aoa wr wb,
- Can someone please help me for qn 2, how do we know that the examiner wants the values of part 'bi' to 2 significnt figures, and for part 'bii', to 2 decimal places?
- Secondly, why is the ms stating that the ratio calculated in 'b ii' must be I:Zn and not the inverse, i mean i did it as Zn:I, but the ms clearly states not to do that:/
- And for part 'e' of the same qn, the reasons for the anomalies in the ms don't quite agree with my understanding, can someone please elaborate?

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w09_qp_51.pdf
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w09_ms_51.pdf

MaxStudentALevel xhizors and @ all other p5 candidates
Thanx a lot :)
 
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Are you sure? Cause ms says it should be an initial straight line but should terminate in a curve?
oh the examiner reports says " Most candidates drew a straight line rather than a line which curved upwards after a pressure of around 200kPa"

i am one of these "most candidates" lol so it is supposed to be a line which will curve after 200kpa
 
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Haniya Khan It'd be better if you could post a question related to it. In general, for serial dilution you take a part from the solution, dilute it, and for next dilution take a part from the diluted solution. For example, if you have initially a sol of conc 1mol/dm^3, take one part this and nine parts distilled water. This would give you a solution of conc 0.1 mol/dm^3. Next take one part of 0.1mol/dm^3 sol and add nine parts water to get a solution of 0.01 mol/dm^3.
 
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i just want to be sure if i am doing the serial dilutions correctly
Lets say i have 2 moldm^-3 of and acid...
and i am making my total volume constant to 100 cm^3
I want a solution of acid with concentration 1 moldm^-3
So in this case will case i will add 50 cm^3 of distilled water and 50cam^3 of acid
now lets say i want to make a concentration of 0.5 moldm^-3
so i will add 25 cm^3 of acid n 75 cm^3 of distilled water
(Please tell me ASAP...if i am correct or not)
JazakAllah!
 
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oh the examiner reports says " Most candidates drew a straight line rather than a line which curved upwards after a pressure of around 200kPa"

i am one of these "most candidates" lol so it is supposed to be a line which will curve after 200kpa
Well according to CIE a line can mean a curve or a straight line,but a straight line means it's only a straight line.
CIE is weird.
 
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