Paper 5 Tips !! :)

[kitty_toxic]

have you solved p5 may/june 2007 Q.2) part e) find x for HgClx??? my gradient keeps coming at 0.74, but how r we supposed to calculate the value of x?

 

[Zari]

Asalamualikum can anyone tell me how to do O/N 09 /51 Q1 part d and e ? what concentrations and volumes should we take for the acids ?

 

[Boss.Mentalist.Awesome]

When they say "step by step discription including..." then you explain the whole procedure including the points the question states.
When it says "step by step discrip. by decribing how..." then you only describe the points mentioned.

JazakAllah khair ....thanx for the help!!!

 

[mariamalik]

Why did you multiply NaOH with 0.1 & D with 10

 

[Student12]

we're taking the 10 cm3 of water layer and 25.0 cm3 of ehtre layer as the vol of succinic acid.
we know that the no of mole of NaOH=2 x no of mol of succinic acid.
because NaOH has one OH gp and succinic acid has two.
so,
Mol of NaOH= 0.1 x B = 0.1B
Mole of succinic acid in water layer = D x 10 = 10D
so 0.1B= 2(10D)
D = 0.1/20 B
get it?

How will i do such question in exam !!

 

[Student12]

we're taking the 10 cm3 of water layer and 25.0 cm3 of ehtre layer as the vol of succinic acid.
we know that the no of mole of NaOH=2 x no of mol of succinic acid.
because NaOH has one OH gp and succinic acid has two.
so,
Mol of NaOH= 0.1 x B = 0.1B
Mole of succinic acid in water layer = D x 10 = 10D
so 0.1B= 2(10D)
D = 0.1/20 B
get it?

Thats to find the concentration yea?

 

[knowitall10]

Why did you multiply NaOH with 0.1 & D with 10

How will i do such question in exam !!

Don't worry, read my explanation and try yourself.
And Sister mariamalik what is the equation for calculation moles of a solution? Mol = vol x conc right? That's what i am doin here. If you still don't get it, please tell me I'll be pleased to help you.

 

[knowitall10]

Thats to find the concentration yea?

yep.

 

[Ash1994]

http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_w08_qp_5.pdf
Part 1d anybody?
what does the gradient represent

 

[kitty_toxic]

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]

 

[Zari]

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]

same dbt

 

[knowitall10]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w08_qp_5.pdf
Part 1d anybody?
what does the gradient represent

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

 

[knowitall10]

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]

same dbt

Good question We didn't get through that one either

 

[Zari]

Good question We didn't get through that one either

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

 

[knowitall10]

MaxStudentALevel u had the same question right? if u got the answer, we need an explanation
Jazaki Allahu Khair!

 

[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).