OCR A2 Chemistry Unit 5, F325 15th June 2015

Reply 1180

Mutleybm1996

19

Original post by BP_Tranquility

I got 33/40 in my assessed practicals- what kind of marks do I need to get in my F324/F325 exams to get an A* overall?

*gulp* very high A's!
Around 55 for F324
Around 85-90 for F325

Edit: oops, someone beat me

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Reply 1181

Mutleybm1996

19

Original post by sneha2096

Guys if anyone has done the OCR past paper for F325 June 2013. There is a mistake in the mark scheme for q 4d (ii) for the moles of HCOOH it should be 0.64 (what my teachers have said).
So don't think it is the end of the world like I did when I did the past paper.

Well they're wrong
It's 0.64-0.4=0.24
I don't have the paper with me but I believe it's because 0.4 moles HCOO- form the HCOONa so you have 0.24 HCOOH left. I can't remember the exact question or reaction but it's something like that

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(edited 9 years ago)

Reply 1182

Captain Anonymous

14

Original post by Mutleybm1996

*gulp* very high A's!
Around 55 for F324
Around 85-90 for F325

Edit: oops, someone beat me

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Hahaha yeah I go there first :wink:

it's not impossible, but need very high marks!

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Reply 1183

Captain Anonymous

14

Original post by sneha2096

Guys if anyone has done the OCR past paper for F325 June 2013. There is a mistake in the mark scheme for q 4d (ii) for the moles of HCOOH it should be 0.64 (what my teachers have said).
So don't think it is the end of the world like I did when I did the past paper.

They're wrong. You have to work the moles present in excess.

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Reply 1184

Mutleybm1996

19

Original post by Captain Anonymous

They're wrong. You have to work the moles present in excess.

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I think my answer explains it? Well that's what I thought at the time, could be wrong!

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Reply 1185

sneha2096

7

Original post by Mutleybm1996

Well they're wrong
It's 0.64-0.4=0.24
I don't have the paper with me but I believe it's because 0.4 moles HCOO- form the HCOONa so you have 0.24 HCOOH left. I can't remember the exact question or reaction but it's something like that

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why did u minus 0.4?

Reply 1186

Captain Anonymous

14

Original post by sneha2096

why did u minus 0.4?

As you have to work out the moles which are present in excess

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Reply 1187

sneha2096

7

Original post by Captain Anonymous

As you have to work out the moles which are present in excess

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I am sorry if this is annoying but why? It doesn't say we need to find it in excess.

Reply 1188

AnnekaChan173

18

Original post by sneha2096

I am sorry if this is annoying but why? It doesn't say we need to find it in excess.

Because the HCOOH reacts with the NaOH to make the conjugate base, HCOO-
The excess is the acid we have left over. We work out the pH from the acid remaining, as Mutley said

(edited 9 years ago)

Reply 1189

Yua

14

7 14 15 in ISA so total to 36, honestly not pleased at all

retook the 7 one and don't think i did too well :frown:

Reply 1190

AnnekaChan173

18

Original post by Yua

7 14 15 in ISA so total to 36, honestly not pleased at all

retook the 7 one and don't think i did too well :frown:

Could be worse much worse, honestly. That should be an A. I wish I got 38+ too tbh

Reply 1191

Yua

14

Original post by AnnekaChan173

Could be worse much worse, honestly. That should be an A. I wish I got 38+ too tbh

What did you end up getting?

Reply 1192

Mutmit287

22

I so wish I knew what I got in my practicals, no matter how hard I ask my college will not tell us our marks!!

To be fair there is nothing I can do about them now but I would still like to know whether I have done enough for an A (last year they told me I had and I clearly hadn't as I got a B in it)

I don't understand why the won't tell us, they it's because they don't won't us worrying about grade boundaries which have yet to be decided but it's really frustrating as I would have liked to have been the one who decided whether I needed to do another one or not, not my teacher!!

Hopefully I got around 36!! I know I got 9 or 10 on the qual out of 10 as he said nobody got below 9 in our class... I can only estimate how I did on the others... I hope around 13/14 out of 15 on the eval and 14/15 out of 15 on the Quan at least!! I'm being hopeful!?!?

Is it just my college that does this?? Does everyone else's release your marks??

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Reply 1193

Saywhatyoumean

10

Could they ask us about a titration that's not in the textbook?

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Reply 1194

Yua

14

Original post by Saywhatyoumean

Could they ask us about a titration that's not in the textbook?

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What do you mean

Reply 1195

AnnekaChan173

18

Original post by Yua

What did you end up getting?

37, didn't go up in my last try. 8, 14, 15.

Original post by Saywhatyoumean

Could they ask us about a titration that's not in the textbook?

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Unlikely. We might get chemicals we don't know, but they'd tell us what it's similar to.

(edited 9 years ago)

Reply 1196

TheLegalDealer

9

Has anyone done the NMR evaluative ? what kinds of things should I go over/ revise ? and is it really as hard as people say ?

Thanks in advance !

Reply 1197

esrom.french

does anyone know what colour we are actually suppose to know for the transition metals?? As i am struggling to know which one exactly , my teacher gave a whole long list of them but didnt say which ones to learn off by heart. In addition i got my practical assessment tomorrow and i really need help, the qualitative on transition metal. Any help would be great. PM if you would like.

Reply 1198

Regina15

2

Hi everyone, has anyone done the qualitative task on precipitation reactions and copper (I) or something like that? Thanks :smile:

Reply 1199

SchoolKid.

11

Original post by AnnekaChan173

Could be worse much worse, honestly. That should be an A. I wish I got 38+ too tbh

Original post by AnnekaChan173

Because the HCOOH reacts with the NaOH to make the conjugate base, HCOO-
The excess is the acid we have left over. We work out the pH from the acid remaining, as Mutley said

Is this always the case when calculating pH?

OCR A2 Chemistry Unit 5, F325 15th June 2015

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