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# ocr a f325 revision thread watch

1. (Original post by hussaincute)
does any one have pictures of the actual paper?
You can't show those publicly yet.

(Original post by otrivine)
for the optical isomers will they allow ECF?

Cause I did Fe in the middle with 2 C2o4 2- and 2 h2o

cause I was thinking in order for optical to occur there either has to be 3 bidentate, or 2 mono or 2 bidentate,

cause it put in bracket (C2O4)2
There probably won't be ECF, it was only 2 or 3 marks.

(Original post by NerdMeister)
Can someone please explain how they got their answers for the rate of reaction after 40 seconds and the rate constant? Thanks
You draw a tangent to the graph at t=40, and the gradient is the rate. The rate constant is then found by doing rate/conc.
2. (Original post by NerdMeister)
Can someone please explain how they got their answers for the rate of reaction after 40 seconds and the rate constant? Thanks
Rate after 40s = dy/dx at 40.

k*half life=ln2 for rate constant
3. (Original post by needtosucceed=))
where you had to name the processes it was precipitation, redox, ligand substitution in that order right?
I don't think you had to name the precipitation reaction, but it was that order.
4. (Original post by PythianLegume)
You can't show those publicly yet.

There probably won't be ECF, it was only 2 or 3 marks.

You draw a tangent to the graph at t=40, and the gradient is the rate. The rate constant is then found by doing rate/conc.

But I am sure, I did it right it was (c2o4)2 which means two are present and u put 2 h2o
5. (Original post by alow)
Rate after 40s = dy/dx at 40.

k*half life=ln2 for rate constant
I think that's what I did, but I'm not sure if the numbers I used were right, do you remember what numbers you used for dy/dx?
6. (Original post by PythianLegume)
Why, because I was confident on the paper? Someone has to do well.
Do your sweaty asian parents say they will burn your ball sack of if you dont excel in exams? Because i hope you fail massively and they burn your **** off too
7. (Original post by NerdMeister)
I think that's what I did, but I'm not sure if the numbers I used were right, do you remember what numbers you used for dy/dx?
I think mine were 3.25/75 or something close to that, got an answer of 0.04ish i think
8. (Original post by otrivine)
was the Ferrate, Feo4 2- ?

what was the equation for first one?

was it Fe +3/2cl2 --> FeCl3?
I did FeO3
9. (Original post by Jack9909)
That was my train of thought, although I havent seen anyone who agrees yet!
Yeah somebody disagreed with me, and although I think I could counter their reasons why, I'm not too sure and can't be bothered now.
10. (Original post by DudeBoy)
I did FeO3
it has a -2 charge, this was a question from the stretch and challenge in book, it was FeO4 2-
11. (Original post by DudeBoy)
I did FeO3
Google Ferrate(VI), it is FeO4(2-)
12. (Original post by NerdMeister)
I think that's what I did, but I'm not sure if the numbers I used were right, do you remember what numbers you used for dy/dx?
Hmm, I just drew a tangent at t=40 and found the gradient :/
13. Anyone got a mark scheme yet? Starting to forget the questions
14. (Original post by alow)
Google Ferrate(VI), it is Fe2O4(2-)
the question told you it had an oxidation state of 6 (VI) therefore it has to be FeO4 2-
15. what did people get for the equation for fecl3 reacting with water to form solution X?
16. (Original post by Little Wing)
Hmm, I just drew a tangent at t=40 and found the gradient :/
I'm afraid that's incorrect - that gives the initial rate of the reaction, not the rate of reaction after 40s.

I think I've lost 20-30 marks at least and am convinced I have an E or U (yes, I know that's extreme, but I've spent so long failing I kind of expect low grades. Seriously, I've struggled since primary school. So sorry if I'm being over dramatic). I just get this horrible feeling I've going to have history repeat itself on results day of failure...
17. (Original post by Benjy100)
Are marks lost if I represented aluminium ethanoate like this ... Al(CH3COO-)3 with the minus sign there? Or do they overlook such things?
not sure now
18. (Original post by Crabbiey)
I'm afraid that's incorrect - that gives the initial rate of the reaction, not the rate of reaction after 40s.

I think I've lost 20-30 marks at least and am convinced I have an E or U (yes, I know that's extreme, but I've spent so long failing I kind of expect low grades. Seriously, I've struggled since primary school. So sorry if I'm being over dramatic). I just get this horrible feeling I've going to have history repeat itself on results day of failure...
I am afraid I feel the same way I can understand how it feels
19. (Original post by Crabbiey)
I'm afraid that's incorrect - that gives the initial rate of the reaction, not the rate of reaction after 40s.

I think I've lost 20-30 marks at least and am convinced I have an E or U (yes, I know that's extreme, but I've spent so long failing I kind of expect low grades. Seriously, I've struggled since primary school. So sorry if I'm being over dramatic). I just get this horrible feeling I've going to have history repeat itself on results day of failure...
The initial rate would be a tangent at t=0
20. (Original post by Sweatynerd)
Do your sweaty asian parents say they will burn your ball sack of if you dont excel in exams? Because i hope you fail massively and they burn your **** off too
Get off this thread cause you're clearly too rude to talk to others and jealous just cause not everyone sucks at Chemistry as I'm assuming you do!

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