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All Chemistry A2 students, the planning question this summer...

Well the previous thread for AS helped a lot of students and even me so i just thought ill start another for A2 now that as is down.
My teacher hinted to througly read the tests. "You are required to plan a series of tests to identify three compounds and to plan a simple
procedure to separate the cations in two of the compounds."

Hmm so wht do u guuys guess? And Babar where r u man? didnt hear from u for so long. Any hints on the planning question..
And neo dont be ethical dude. I aint giving the quesiont. Just discussing the possibilities.

Ill dig up more info tomoroow. Guys help wud be appreciated. We previously helped in AS so plz help us in A2..

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Reply 1
If it was to separate ions, how would you do it?
smashingdude, are you doing A2 practical as well!?!?
Reply 3
well Mustard Man i wudnt have posted the thread if i hadnt taken A2 :biggrin:
I have take the whole Alevel course (Thats done in one year). currently doing Alevels(as+a2) in Maths and Chem. I know most of u do Alevel in 2 years(As the first and A2 the second) but here, we do Alevel in 1 year(thats both As and A2)

Anyways UPDATE on the practical. My teacher gave me a planning question for practice. She said to plan to precipitate out Cations. And she stressed on White Precipitate So wht we can expect in the final question is to precipitate out cations which form white precipitates. Ill dig more info on it.
guys HELP WUD BE GREATLY APPRECIATED..
Smashingdude
well Mustard Man i wudnt have posted the thread if i hadnt taken A2 :biggrin:
I have take the whole Alevel course (Thats done in one year). currently doing Alevels(as+a2) in Maths and Chem. I know most of u do Alevel in 2 years(As the first and A2 the second) but here, we do Alevel in 1 year(thats both As and A2)

Anyways UPDATE on the practical. My teacher gave me a planning question for practice. She said to plan to precipitate out Cations. And she stressed on White Precipitate So wht we can expect in the final question is to precipitate out cations which form white precipitates. Ill dig more info on it.
guys HELP WUD BE GREATLY APPRECIATED..

Hey SmashingDude,
I'll ask my teacher tomorrow and see what I can get from him.
Reply 5
Thats great Aburruman. Post the info here plz. Others plz dig up info from firends/teachers. Ill try to get from my teachers.
My teacher hinted transition metal percipitates... Anyone have any idea?
Does it mean percipitate it with NaOH/NH3. Once you percipitate it does it mean its seperated?
Reply 7
I will give A2 next year. Can't help you now...
Reply 8
how r u aburumman... did u ask hussainy about the planning exercise.. ??
Reply 9
Is this AQA?!
edexcel
Reply 11
hello fellow chem A-level studying peoples!
well i got some good hints from places :wink:

The planning question, by elimination should be the identification of 3 unknowns, A B and C. You may or may not be given NaOH. Anyways you probably have to identify the NH3. This is easy with NaOH at hand and just as easy without :wink:
Anyways the 2 unknowns then need to be identified and seperated. It is going to be transition metal compounds and i guess again by elimination one has to to be a zinc (sulphate/nitrate or w/e) as it is one of the few which is a white ppt formation upon reaction with NaOh. Then i guess you can see wher the NH3 would come in. And then simply seperate using the standard method. EASY PEESY! :biggrin:
Hope this helpS!
GooD LUck!
Reply 12
Now this is wht i am talking about. Thanks dude for the info. Ill be getting some more info soon and ill post it here. Guys help wud be greatly appreciated.
Thanks gamma_ray. nice radiations.... :wink:
har1s
how r u aburumman... did u ask hussainy about the planning exercise.. ??

Im fine, thank you.
No, I didn't talk to him today.
Reply 14
interesting stuff.. gamma guy :smile:
Reply 15
gamma_guy
hello fellow chem A-level studying peoples!
well i got some good hints from places :wink:

The planning question, by elimination should be the identification of 3 unknowns, A B and C. You may or may not be given NaOH. Anyways you probably have to identify the NH3. This is easy with NaOH at hand and just as easy without :wink:
Anyways the 2 unknowns then need to be identified and seperated. It is going to be transition metal compounds and i guess again by elimination one has to to be a zinc (sulphate/nitrate or w/e) as it is one of the few which is a white ppt formation upon reaction with NaOh. Then i guess you can see wher the NH3 would come in. And then simply seperate using the standard method. EASY PEESY! :biggrin:
Hope this helpS!
GooD LUck!

OK I’m a bit lost.

First of all (using the edexcel user guide) all transition metals form a ppte with NaOH or NH3(not in excess)

Mn(II) Off White
Iron(II) green ptt
Ni(II) Green ptt
Co(II)- Blue ptt
Cu(II)-Blue ptt
Zinc(II)-White ptt
Cr(III)-Green ptt.


Now if you add excess NH3(aq)

Cobalt(II)- ppt dissolves to give brown solution.
Nickel(II)- ppt dissolves to give blue solution
Copper(II)-ppt dissolves to give deep blue solution
Zinc(II)-ptt dissolves to give colourless solution.

Others are insoluble in NH3(aq) excess.

So step one could be add NH3 to the 3 samples. Note the colours of ptt. Colours will identify the metal(cation)

Step 2. Are you saying they might say sample A and B have mixed together. Separate the cations in them? For this to work one sample would have to be soluble in excess NH3(aq) and the other must be insoluble in excess NH3(aq).

So we add excess NH3(aq). One of the ptt will dissolve. We filter off the ppt that did not dissolve (filter paper funnel) and hey presto cations separated??????????

Am I on the right lines here?
Reply 16
hey RMIM - i think wat u typed is correct.. but i dont think its going to be so simple
Reply 17
Ok

That makes sense once you've got to the point where there are only 2 transition elements to distinguish between. But how do know they will give us NH3 - more likely they'll give us NaOH. But what happens if they dont give us even NaOH :confused:

Will they tell us to identify 3 and separate 2 ???

usman_s/RMIM - i think we're on the right track but perhaps a little simplistic.
Reply 18
Kieny
Ok

That makes sense once you've got to the point where there are only 2 transition elements to distinguish between. But how do know they will give us NH3 - more likely they'll give us NaOH. But what happens if they dont give us even NaOH :confused:

Will they tell us to identify 3 and separate 2 ???

usman_s/RMIM - i think we're on the right track but perhaps a little simplistic.

I don't know anything. that's why Im asking you lot.
And without NH3(aq) -

NaOH will disolve zinc II and chromium in excess.

So if they give us either NaOH or NH3(aq), I think I can do something with them if I get the right combination of transition metal.

The key, I get one that is not soluble in excess and one that is.

Any other ideas?
Reply 19
Ye - thats how im planning to go ... (Sorry no pun intended)

NOTE: Zn 2+ is a big probability as is NaOH instead of NH3. Im nor certain but ive got the feeling it might be those.

Just islolate one of the other transition metals by either rendering it ppt or solution by adding excess. You can remove the ppt from solution and identify the cation you want whether it be the one left in soln or in ppt.

I jus cant fathom what additional little snide trick their gonna add in ...:eek:

ALSO: Does anyone out there have any indications of whats going on with the Boiling point that we're gonna get 2moz?

I know the theory on how to get the boiling point but nailing it and seeing those tiny bubbles is ridiculous - i keep overshooting the Temp :grr:

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