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OCR Chemistry A F325 - Equilibria, Energetics and Elements - 12th June 2013

Unofficial mark scheme!!!
https://docs.google.com/document/d/1WICd6ufVwBxfVz10_b4Hqd85oSv2FMQTrcll_t5qD0k/preview?pli=1&sle=true

It says I need to request access, is that supposed to happen? :/

Reply 181

damnsaiyan

2

Original post by gemmabug

It says I need to request access, is that supposed to happen? :/

It works for me.

The structure of the ligand is wrong as there should be a hydrogen missing from one of the oxygen, so the ligand has an overall -1 charge.

Reply 182

BananaWhale

4

I was baffled by the last question and paniced.

But I wrote one thing which was "7H20", recon that'll get one mark? haha.

Goodbye University of Nottingham :frown:

(edited 10 years ago)

Reply 183

niki135

2

Guys can someone PLEASE be honest and tell me how many marks ill lose for writing methanoic acid as COOH :frown:

erghhhh but I said all the 'when acid is added/alkali added stuff' would I lose ALL 7?!

Reply 184

Brutal_Pigeon

5

Original post by emilykateh

Thats great you found it ok, hope you did as well as you think. However I'm not sure it's fair to say people are 'making it out' to be difficult, that's just their take isn't it.

That's what I said. People are saying it was hard. I acknowledged it.

I'm not forcing it on anyone that it was easy and they shouldn't believe otherwise.

Reply 185

Sly1

6

I think it was easier than January's paper but with a few hard questions starting from question 5 of the paper onwards.

Reply 186

niallh1995

I think I got 9H20 for the last question but I was rushing as the time went out. I just hope I beat my previous grade which was a C. I didn't revise last time and therefore I'm a fool.

Reply 187

niallh1995

Original post by Brutal_Pigeon

With the last question, I somehow ended up with NiSO4 . 9H2O.

I worked out there being 0.08 moles of water present... then right at the end to get water of crystaillsation, I did (0.08)/(moles of NiSO4 in the 1.38g, that being 1.38/154.8) which ended up being 8.97 - close enough to 9. Everyone walked out of the exam saying they got 7, and most people in this thread say they got 7. Have I forgotten how to work out water of crystallisation?

I felt like the paper was easy, but long. My write is sore and I am now developing carpal tunnel syndrome as a result of intense revision sunday/monday, computing unit 3 on tuesday, and chemistry today - SO MUCH PAIN! THE PAIN IS GOOD!

I also felt I was running out of time. On the electrode potentials question, I had complete brain-death at the question when it said use redox systems 3 4 and 5 to make 3 equations. I worked out what it was asking right in the last 20 seconds of the exam and only had time to put one down.

Aside from that, I think everything else went fairly well... this was my first time sitting this unit and I didn't find it nearly as difficult as some people are making it out to be.

</brag>

I got 9H20 also but I want to see the paper again so I can have another crack at it.

Reply 188

Mathlover123

11

Original post by Amz1217

Unofficial mark scheme!!!
https://docs.google.com/document/d/1WICd6ufVwBxfVz10_b4Hqd85oSv2FMQTrcll_t5qD0k/preview?pli=1&sle=true

There was one mistake the reaction of iron with chlorine was written as Fe3+ + 3CL- ----> FeCl3
It was solid Iron thus the reaction would be
2Fe + 3Cl2 ----> 2FeCl3

Reply 189

Gulzar

2

Original post by LaChiffre

Oh i didnt get NiSO4.7H2O :frown:

OMG is that the right answer :eek:

Reply 190

ambrin ox

4

Original post by Mathlover123

There was one mistake the reaction of iron with chlorine was written as Fe3+ + 3CL- ----> FeCl3
It was solid Iron thus the reaction would be
2Fe + 3Cl2 ----> 2FeCl3

can you have multiples???

Reply 191

ambrin ox

4

instead of redox, i wrote oxidation reaction.....\*facepalm...

Reply 192

eggfriedrice

16

Original post by ambrin ox

can you have multiples???

Multiples are fine. (:

Original post by niki135

Guys can someone PLEASE be honest and tell me how many marks ill lose for writing methanoic acid as COOH :frown:

erghhhh but I said all the 'when acid is added/alkali added stuff' would I lose ALL 7?!

Hmm. It would be unfair that you'd lose all marks, especially since you have the general idea.

Reply 193

Brutal_Pigeon

5

Original post by ambrin ox

instead of redox, i wrote oxidation reaction.....\*facepalm...

I put precipitation. At least you got it half-right :biggrin:

Reply 194

Amz1217

OP

Original post by Mathlover123

There was one mistake the reaction of iron with chlorine was written as Fe3+ + 3CL- ----> FeCl3
It was solid Iron thus the reaction would be
2Fe + 3Cl2 ----> 2FeCl3

I didn't write the mark scheme mate, I just got it off the other F325 thread...regardless I kinda cocked up that question on Fe and the multiple experiments, hmmm

Reply 195

scastleman1

i wrote 7H2O.NiSO4 instead of the other way round.... will i lose marks for this?

Reply 196

Liberty_Alice

Has anyone got the paper itself?

Posted from TSR Mobile

Reply 197

Amz1217

OP

Original post by scastleman1

i wrote 7H2O.NiSO4 instead of the other way round.... will i lose marks for this?

I highly doubt that matters, you should be fine

Reply 198

chem99

Original post by Amz1217

Unofficial mark scheme!!!
https://docs.google.com/document/d/1WICd6ufVwBxfVz10_b4Hqd85oSv2FMQTrcll_t5qD0k/preview?pli=1&sle=true

The equation for the reaction (2 Mark)
2[Fe(H2O)6]3+ + Zn → 2[Fe(H2O)6]2+ + Zn2+

I'm sure it never asked for the reaction just the formula of [Fe(H2O)6]2+

(edited 10 years ago)

Reply 199

Emma2129