AQA CHEM5 A2 Chemistry - 19th June 2013

Reply 2720

username1054067

2

Original post by Anshul91

co-ordination number is 6, it didnt ask for the co-ordination number?

Yeah i know it didn't

Original post by AndyMacCormick

Nah it is still 6 as there are 6 dative covalent bonds

But isn't cordination number the number of ligands attached, not bonds forming.

Ethane 12 diamine is bidentate

Reply 2721

erniiee

13

Original post by Edmundith

If they wanted the spectator ions in the equations (ie: Na+, H+ etc.), they would have made it very clear in the question, because no question in any AQA exam has asked for those before.

Exactly! Those are part of the reagent and don't participate in the reaction. You'd only lose marks if the asked for the reagent and you gave CO32- without the Na!

Reply 2722

Mocking_bird

11

Original post by erniiee

Aha that question was tricky! Luckily it was in the June 12 paper (or something very similar) so I managed to work it out..this whole paper was horrendous though! Oh yea how did you find Bio?

Bio was a bit dodgy !
Disappointed in the lack of biology actually in it but the essays were nice at least :smile:

Which essay did you do and how did you find it? Think you've done enough for your offer? :biggrin:

Reply 2723

marleyxd

Original post by erniiee

Wow surprised you had enough space! I suppose you will, because in past mark schemes they haven't penalised people putting H with the Cl-s as HCl. As long as its appropriately balanced I'm sure you'd get all the marks!

Yeah i wasn't sure if i got the one with the H's and Na's right but im sure about the ionic ones. If one is wrong and the other is right do you think i will still get the mark..

Reply 2724

Padouken

7

Original post by brittanna

As much as I would love these to be the grade boundaries, I wouldn't say the paper was more difficult than June 2012.

My guess for grade boundaries (also based on how other people I spoke to found the paper):

80 - A*
73 - A
65 - B
57 - C
48 - D
41- E

IMO the paper was way more synoptic than June 12. June 12 just took a while to get through, it wasn't that hard. ( did as our mock and lost like 8 marks). Very long test though.

Reply 2725

itssochaotic

so what was the answer to the final temperature of water question?

Reply 2726

theslav

Original post by yarshad

Yeah i know it didn't

But isn't cordination number the number of ligands attached, not bonds forming.

Ethane 12 diamine is bidentate

Definition of bidentate : a ligand that forms two co-ordinate bonds with a metal ion

Co-ordination number : number of co-ordination bonds a metal ion has in a complex

Reply 2727

SexyAndIKnowIt.

1

Does anyone have an unofficial mark scheme.

Was it me, or was that paper extremely difficult !!!

Reply 2728

erniiee

13

Original post by brittanna

As much as I would love these to be the grade boundaries, I wouldn't say the paper was more difficult than June 2012.

My guess for grade boundaries (also based on how other people I spoke to found the paper):

79 - A*
72 - A
65 - B
57 - C
48 - D
41- E

I suppose, I think it will either be the same or less.

The only reason I think it was harder than the June 12 was because of the amount of mathematical manipulation involved in the calculations (which were a lot more than in the june 12!)

I think that will draw them down, but knowing AQA, they definitely wont be lower than 2 or 3 marks from the June 12.

Reply 2729

Anshul91

Original post by yarshad

Yeah i know it didn't

But isn't cordination number the number of ligands attached, not bonds forming.

Ethane 12 diamine is bidentate

no co-ordaination number is the 'number of co-ordinate bonds'

Reply 2730

BobLoblawLawBlog

16

Original post by Padouken

IMO the paper was way more synoptic than June 12. June 12 just took a while to get through, it wasn't that hard. ( did as our mock and lost like 8 marks). Very long test though.

There were a lot of quite difficult questions, but I also think it would also be quite easy to get the first couple of marks on these questions (e.g. calculating moles on the last question). But yeah, maybe it will be a bit lower. But I still think the fact that there were a lot of marks on transition metal colours (in an easier format than June 2012) will increase the grade boundaries. Hopefully i'm wrong though :tongue:

.

Reply 2731

Vip3rgt9

10

Original post by yarshad

When the question asked to draw the cobalt thing with these ligands substituted in?

Is the cordination number with 1,2 ethandiamine ligands 3??

I pity the examiner who has to mark my drawing :smile:

It was quite messy.

Reply 2732

erniiee

13

Original post by Mocking_bird

Bio was a bit dodgy !
Disappointed in the lack of biology actually in it but the essays were nice at least :smile:

Which essay did you do and how did you find it? Think you've done enough for your offer? :biggrin:

Yea far too much interpretation of data/graphs :/ hopefully that will bring the grade boundaries down very far though! Have to agree about the essays though, membranes was a dreammmm! Which one did you pick? There was loads to talk about for membranes, although not much from unit 2/4 :/

Original post by marleyxd

Yeah i wasn't sure if i got the one with the H's and Na's right but im sure about the ionic ones. If one is wrong and the other is right do you think i will still get the mark..

Hm, they may say ignore other equations, but honestly I don't know :redface:

best bet is to look at mark schemes and what they have said in the past!

Reply 2733

Padouken

7

Original post by itssochaotic

so what was the answer to the final temperature of water question?

I got 311 and or 300 and something. Low 300s though. Did you convert enthalpy into heat energy by multiplying by moles?

Reply 2734

BobLoblawLawBlog

16

Original post by erniiee

I suppose, I think it will either be the same or less.

The only reason I think it was harder than the June 12 was because of the amount of mathematical manipulation involved in the calculations (which were a lot more than in the june 12!)

I think that will draw them down, but knowing AQA, they definitely wont be lower than 2 or 3 marks from the June 12.

Good point. I guess I've been assuming that everyone does maths and so will have found that quite simple, but this obviously isn't the case. So yeah, maybe I did over estimate them a bit (hopefully :biggrin:

).

Reply 2735

Vip3rgt9

10

Original post by itssochaotic

so what was the answer to the final temperature of water question?