ocr a f325 revision thread

Reply 3620

meeee

Original post by emah123

was is just me or was that the HARDEST PAPER EVER. good bye to medical school :frown:

ahh that's what I'm thinking :frown:

I so hope I've got a B or I'll be so upset for the next year.. min. God it's stressing me out looking at the answers people got and I didn't!

Reply 3621

Benjy100

5

Original post by keepontrying

I meant to put 6H20 at the end I just forgot to type it and yours doesn't balance electrically but still may be correct!

It does o.O

Oops I meant +3

Reply 3622

Allotropy

Overall I thought the paper was hard but doable. Looking through the answers people have posted I seem to be the only one who calculated a value of 3.55 for the buffer solution pH, did anyone else get this?

Reply 3623

ShogDX

5

Original post by talliehughes

I got both 3.99 and put 16.75 for the kc but I don't think they'll be too picky when it comes to rounding numbers

The 16.75 was right, but they asked for 3 sigfig :/

Reply 3624

freetown

6

Original post by Little Wing

NH3 acts as a reducing agent anyone?

I guessed acting as a reducing agent as well. Is it right though ?? :\

... by the way here is the link for the 'Dimethylglyoxime' structure

Reply 3625

jess_m94

12

Original post by Little Wing

NH3 acts as a reducing agent anyone?

I put that it acted as a proton accepter, but I could be wrong :smile:

Reply 3626

FailedMyExams

8

Hoping it's like 62 for a B :L

Reply 3627

louci

7

Original post by Allotropy

Overall I thought the paper was hard but doable. Looking through the answers people have posted I seem to be the only one who calculated a value of 3.55 for the buffer solution pH, did anyone else get this?

how did u work it out man

how were u meanto work out the conc of the salt ????

Reply 3628

amin666

why order of H2O was zero?

Reply 3629

username878045

17

Original post by Little Wing

NH3 acts as a reducing agent anyone?

It was acting as a base.

Reply 3630

Tania2k9

Original post by Allotropy

Overall I thought the paper was hard but doable. Looking through the answers people have posted I seem to be the only one who calculated a value of 3.55 for the buffer solution pH, did anyone else get this?

ib got 3.55/3.57, definitrly out of those two

Reply 3631

Benjy100

5

Original post by jess_m94

I put that it acted as a proton accepter, but I could be wrong :smile:

I put that also - that it acts as a base to accept the proton from that weird molecule.

Original post by freetown

I guessed acting as a reducing agent as well. Is it right though ?? :\

... by the way here is the link for the 'Dimethylglyoxime' structure

Oh for gods sake I misread the question and drew that very molecule but with a hydrogen removed. I thought it wanted the ligand :frown:

Reply 3632

_HabibaH_

8

Original post by tangaroo

i could've sworn it wasn't THAT bad guys?

If you tell me you enjoyed it, I will cry...real tears. :unimpressed:

Reply 3633

MathsNerd1

17

Original post by jess_m94

I put that it acted as a proton accepter, but I could be wrong :smile:

I said this too and that it's used to neutralise excess acid?

Reply 3634

Dslash

Original post by Allotropy

Overall I thought the paper was hard but doable. Looking through the answers people have posted I seem to be the only one who calculated a value of 3.55 for the buffer solution pH, did anyone else get this?

I did, but i'm pretty sure it's wrong.

Reply 3635

Brad0440

Original post by amin666

why order of H2O was zero?

I just wrote because its concentration doesn't affect the rate. I meant to go back at the end to expand on it, but I ran out of time. :s-smilie:

Reply 3636

TauMuon

10

For the redox one I think I did:

2[Fe(H2O)6]^3+ + Al ====> 2[Fe(H2O)6]^2+ + Al^2+

Which seems completely wrong to me. Not sure I should have included the complexes. Oh well. Don't know if that's exactly what I put; can't remember what the Aluminium was oxidised to...

For the ligand substitution one I think I did:

[Fe(H2O)6]^3+ + 6CN^- ====> [Fe(CN)6]^3- + 6H2O

For the use of NH3 in the bidentate ligand question:

NH3 oxidised the ligand (or words to that effect) :s-smilie:

The amount of answers I have no idea are correct or not is too damn high..