Chemistry: Post your doubts here!

[sitooon]

Assalam Alaikum,

The A2 level exams are on the way ... plz do someone upload the A2 chemistry APPLICATIONS section notes.



I'll glad to appreciate you and THANKS !!!! in advanced

 

[AbbbbY]

Don't bother with this ancient stuff. Read the stuff at chemguide.co.uk.
The cambridge booklet is so horribly mundane and full of crap.

 

[sitooon]

Can someone tell me why
1- why they used 7.20 as pka in q 2c(iii) > http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_w06_qp_4.pdf

2- Find %by mass of CU in question 2(c) http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w10_qp_43.pdf

 

[AbbbbY]

Can someone tell me why
1- why they used 7.20 as pka in q 2c(iii) > http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w06_qp_4.pdf

2- Find %by mass of CU in question 2(c) http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w10_qp_43.pdf

2-
Mols of S2O3 = Mols of Cu.
Mols of S2O3= 0.02 = mol/(19.5/1000)
= 0.00039 mol

0.00039 mol in 50cm3
so [Cu2+] = 0.00039/(50/1000) = 0.0078 mol/dm3

mols of copper in 50cm3 = 0.00039
mols of copper in 100cm3 = 0.00078
mass of copper in 100cm3 = 0.00078*63.5 = 0.0495 (this value is mass / 100cm3 thus percentage)

So 0.0495% copper. If you don't get this method, let me know I'll tell you the alternative method.

 

[periyasamy]

Hello guys ,really need help here.Can someone explain both the parts for me.Thanks a lot.......

 

[Thought blocker]

Full paper solved ---> 9701_wO7_qp_22
POST #30

 

[asma tareen]

Can anyone please explain the mechanism of bromination :/????
Suchal Riaz

 

[Thought blocker]

Can anyone please explain the mechanism of bromination :/????
Suchal Riaz

Learn next video

 

[asma tareen]

Thanks

Learn next video

But I cant open youtube :/

 

[Thought blocker]

ThanksBut I cant open youtube :/

Woops!
http://freevideolectures.com/Course...02-Stochastic-Methods-for-Actuarial-Science/6 Can u open this ?

 

[asma tareen]

Nope

Woops!
http://freevideolectures.com/Course...02-Stochastic-Methods-for-Actuarial-Science/6 Can u open this ?

 

[Thought blocker]

Nope

Then a last try
http://www.brownianmotion.co.uk/

 

[asma tareen]

Then a last try
http://www.brownianmotion.co.uk/

I asked about bromination :/ the addition reaction of alkene :/

 

[Thought blocker]

I asked about bromination :/ the addition reaction of alkene :/

Woops! My mistake
http://www.masterorganicchemistry.c...ation-of-alkenes-with-br2-to-give-dibromides/

 

[asma tareen]

Woops! My mistake
http://www.masterorganicchemistry.c...ation-of-alkenes-with-br2-to-give-dibromides/

Thaank u

 

[Suchal Riaz]

asma tareen
http://www.chemguideforcie.co.uk/section102/learningd.html#top

 

[asma tareen]

asma tareen
http://www.chemguideforcie.co.uk/section102/learningd.html#top

Thank u

 

[Thought blocker]

Thaank u

Welcome

 

[AbbbbY]

Can anyone please explain the mechanism of bromination :/????
Suchal Riaz

http://i.imgur.com/UdmuvKL.jpg

Simple enough?


Edit: Just noticed, it's already been answered already. This forum is confusing :S

 

[asma tareen]

http://i.imgur.com/UdmuvKL.jpg

Simple enough?


Edit: Just noticed, it's already been answered already. This forum is confusing :S

Yeah but thanks