Paper 5 Tips !! :)

[xhizors]

I hope this helps brother..

did that help brother
Muhammad Bin Anis

 

[xhizors]

umm ya..its a lil confusing, so when ever thy ask best fit does tat mean da graph can b curve too??? i rely dnt knw!!

yup!

 

[Jiyad Ahsan]

Line of best is not the straight line, its the line with the most points on it
did that help?

umm the line of best fit does not necessarily have to be a "straight line" it just has to show GENERALLY what pattern the results of an experiment follow..and it can be like a sort of an average line.. and neither does it have to pass 'most' points.. it should have an equal displacement of points around it... umm mtlb there should be around the same number of points above the line as below it.. hope i helped

 

[xhizors]

when they ask us to calculate solubility and say :
"The units of solubility are grams per one hundred grams of water (g / 100g water)." What does this mean???? and what formula do we use?
thanx in advance

do read some older key points notes
solubility = (mass of solid x 100) / mass of water

 

[aloha]

Quenching is basically stopping the reaction! Or slowing it down so much that it won't change when you measure it for example placing an amount of solution on ice

can u give me an example????????????????

 

[autumnsakura]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s10_qp_52.pdf

Need some help with question 1(d) of M/J 2010 paper. I don't understnad when they mean they only give 100g of water. So the 100g of water needs to be divided and used for 5 experiments or for each experiment I conduct, I can use 100g of water? If someone could post an answer to part 1(d), I'll be grateful! Thank you!!!

 

[knowitall10]

Can you please tell how you calculated the concentration of the acid after calculating the moles of succinic acid?

By cross multiplying, brother.
For eg:
vol. of 0.10 moldm3 NaOH= 24.3
vol. of succinic acid in water layer= 10
1 mole of NaOH= 2 mol of succinic acid
0.1 x 24.3 = 2( D x 10)
2.43 = 20 D
D = 2.43/20
D = 0.1215
got it?

 

[rafay malik]

xhizors.
I wanted to confirm the method for determining solubility of a substance.
Can we take different masses of the substance In a fixed volume of water (let's say 100cm3) , and stir the solution at a fixed temperature until no more dissolves. Then allow the solution to cool while stirring and note the temperature at which the first crystals appear.

 

[knowitall10]

xhizors.
I wanted to confirm the method for determining solubility of a substance.
Can we take different masses of the substance In a fixed volume of water (let's say 100cm3) , and stir the solution at a fixed temperature until no more dissolves. Then allow the solution to cool while stirring and note the temperature at which the first crystals appear.

Oui.. sorry i am not xhizors but wait till he responds

 

[Boss.Mentalist.Awesome]

May Allah help us all succeed in tomorrows exam....And jazakAllah to people who are putting their efforts to help others out...thanx loadsss.....GOOD LUCK TO ALL..insh'aAllah we all will do very good...and ace the exam !!!
Ameen

 

[Jiyad Ahsan]

Oui.. sorry i am not xhizors but wait till he responds

oui as in french for yes.. OMG a french speaking arabic

 

[Jiyad Ahsan]

umm ya..its a lil confusing, so when ever thy ask best fit does tat mean da graph can b curve too??? i rely dnt knw!!

umm the line of best fit does not necessarily have to be a "straight line" it just has to show GENERALLY what pattern the results of an experiment follow..and it can be like a sort of an average line.. and neither does it have to pass 'most' points.. it should have an equal displacement of points around it... umm mtlb there should be around the same number of points above the line as below it.. hope i helped

 

[Soldier313]

okay listen... go back to the ms.. not the appendix the place where its written "correctly calculates the ratio....."
the place where it says "see appendix" look above it it says what ? "calculation MUST be to 2 decimal places"

Thanx bro.......

 

[Ramsha007]

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!

Hey i am doing the same thing just i have taken x-2.45 y-1.68 then why x is not cuming 0.5 for me

 

[xhizors]

this is my graph.. u rely havin troubl wit tat qustn ha..hope it hlps!!

mines graph is same too but the point is solubility is coming more than 100g shed light plz

 

[MaxStudentALevel]

I

If thats just for xhizors then i ain't answerin ya

Hahahahhaaaaa omg just saw this! No of course not! Just tagged someone in case no one saw it

xhizors could you help me out a bit in part (e) of ON 2007 Q1? All I'm confused about is why are the moles specified to 0.05-.25?

 

[Student12]

oh its like since the gradient of line is constant, umm if from your construction line you find that with one unit of x you have 2 units of y... so umm 2 units of x would give you 4 units of y.
( umm another way of saying it is like 'A man walks seven miles in two hours. What is his average speed? so since his speed is constant, you half the x (time), and half the y(distance).. you have 3.5 miles/hour !)

sorry if i confused you..

LOL you actually confused me !

 

[xhizors]

Omg,thankyou soo much!!! Turns out my coordinates were correct,i just drew curves instead of lines! :/
Yes,i was really stressed out after doing this qn! Really helped! Thanks again!

no u have to draw a curve for lower temperatures!

 

[Farru]

In question q, where we have to design the experiment,, when we are asked to write the conc we are using so we are suppose to write the conc and volumes we are using in table form, or para form??
and do we have to mention how we are doing it, like using unitary method or c1v1=c2v2?

 

[Farru]

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