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OCR A2 CHEMISTRY F324 and F325- 14th and 22nd June 2016- OFFICIAL THREAD

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That paper made me cry.
Have no idea if I did well but I feel my chances of uni are blown
Hahahaha asif I thought I'd aim for A* at the beginning of A2
(edited 7 years ago)
What was the ph of buffer solution and how did you calculate it?
Original post by tcameron
That paper made me cry.
Have no idea if I did well but I feel my chances of uni are blown
Hahahaha asif I thought I'd aim for A* at the beginning of A2


same. but i have already prepared my tears for this paper before it starts.....
What was the answet to this question
Original post by smileez_101
That question on oxidising and reducing agent was 6 marks and I def got that reducing equation wrong because I said it would react with 3 - 6 redox systems instead of just one.
How many marks do people think thats worth?
is anyone working on an unofficial markscheme ?
Original post by nimoooooooo
What was the ph of buffer solution and how did you calculate it?


3.43 I think, and you just worked out the moles used, then divide each by 1000. No need to deal with reacting masses because conjugate base was given. Plug into Kaacidoversalt, then -log c:


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Reply 3706
What was the buffer pH? Really confused me, I don't think the acid was in excess?
Reply 3707
Original post by k.russell
I went for the ol' CuCO3, which is also insoluble but I think it would get the mark no? You want to end up with the Cu(HCOO-), because the carbonate and the acid would definitley react, even if it was solid before


That's true, and overall it may well still work, and so might Cu(OH)2, it's just a dodgey bet considering it technically wanted the Cu2+ ions to be the thing reacting.
Original post by GetOverHere
3.43 I think, and you just worked out the moles used, then divide each by 1000. No need to deal with reacting masses because conjugate base was given. Plug into Kaacidoversalt, then -log c:


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do you think that working out conc of both acid and the salt would be 2/4 marks or 1?
Original post by Hixy
What was the buffer pH? Really confused me, I don't think the acid was in excess?


Acid didn't react. You was adding salt.
Original post by GetOverHere
Kaacidoversalt


This word confused me for a second...
Original post by smileez_101
do you think that working out conc of both acid and the salt would be 2/4 marks or 1?


You was given the conc - I'm assuming you mean moles. I'd like to think you'd get 2/4 but you never know.
Well, I can kiss goodbye to getting an A... and then say hello to my A*, seriously that paper was a breeze!
Original post by nimoooooooo
What was the ph of buffer solution and how did you calculate it?


i calculate the concentration of acid and salt in the buffer using n=cv, then use Ka to find H+(aq) and pH. got 3.43 i think.....
Original post by GillyTheGhillie
Well, I can kiss goodbye to getting an A... and then say hello to my A*, seriously that paper was a breeze!


no
Original post by smileez_101
That question on oxidising and reducing agent was 6 marks and I def got that reducing equation wrong because I said it would react with 3 - 6 redox systems instead of just one.
How many marks do people think thats worth?


I reckon 2 marks for explaining what is meant by oxidising/reducing agents. Then another 2 marks for how Cr3+ it acts as a oxidising agent and then another 2 marks for it as a reducing so you probably lost 2 marks max :smile:

(don't worry I did the same)
(edited 7 years ago)
Too funny 😂😂😂😂😂 oh god!
Original post by GillyTheGhillie
Well, I can kiss goodbye to getting an A... and then say hello to my A*, seriously that paper was a breeze!
What was the answer to the very first question when you add ammonia to CuSO4 or something
Yh I got Sth like that as well I know it was 3. Something I don't remember more!
Original post by lai812matthew
i calculate the concentration of acid and salt in the buffer using n=cv, then use Ka to find H+(aq) and pH. got 3.43 i think.....
Original post by GillyTheGhillie
Well, you should have revised then, everyone I have spoken to has said that it was an easy paper.


Don't be so rude! You don't know how much revision they did.

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