Year 12s: what will be the first way you research your future options? >>

AQA CHEM5 A2 Chemistry - 19th June 2013

Scroll to see replies

Why does P4O10 have a lower melting point than Si02?

P4O10 simple molecule. doesnt take much heat energy to break weak VDW intermolecular forces
SiO2 is giant covalent (Macromolecular) structure so it takes vast amount of heat energy to break all the strong covalent bonds between atoms.

Original post by Croydon'Stepper

I have no idea. I said it uses electricity from the mains which is created using fossil fuels.

It was being recharged whihc meant an external voltage needed to be applied, which uses energy from the combustion of fossil fuels :smile:

so youre right.

Reply 2701

AndyMacCormick

Lots of quite strange questions but overall it was quite a nice paper I think! Needed a D on that paper to get the A so I am quite confident! I will happily help someone start an unofficial mark scheme if anyone is up to it!

Reply 2702

Divergent

What's the overall feel of the paper?
I didn't sit it because i'm stuck in hospital.

Reply 2703

MHay

Original post by SuziieB

Guys I just calculated that I need 75 ums to get an A. What mark could that be??

(Please, be a C, please be a C...)

Posted from TSR Mobile

75 UMS is a C, 62.5%.

Reply 2704

wrnicholls

Grade boundary predictions ?

Reply 2705

marleyxd

Original post by erniiee

I don't know why people are implying that they wouldn't accept CO32- and Cl- as even without the other ions these are the overall equations?

The reagent is Na2CO3, but the reaction is between the carbonate ion and the complex, the sodium ions/protons of HCl are just spectators.

Highly doubt there will be any marks lost for not showing them!

This

I wrote both for each reaction.. will i still get the marks?

Reply 2706

username1054067

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

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

Reply 2707

username1054067

Original post by Divergent

What's the overall feel of the paper?
I didn't sit it because i'm stuck in hospital.

will you do the paper another time? or?

Reply 2708

wrnicholls

Original post by AndyMacCormick

Good for you!

Reply 2709

Anshul91

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??

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

Reply 2710

HELPIMSTUCK

Original post by SuziieB

Guys I just calculated that I need 75 ums to get an A. What mark could that be??

(Please, be a C, please be a C...)

Posted from TSR Mobile

It is a C

I need 74 (depends on the ISA though)

Reply 2711

AndyMacCormick

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??

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

Reply 2712

zbubbly

what was the answer to why the current flowed from right to left, i put something like there were less electrons in the 1.00 cuso4 than the 0.2 cuso4 or something like that, is that right??? also the answer for why co2 is released is that it requires electricity for the backwards reaction and electricity can be made by burning fossil fuels, completely ****ed up the cobalt catalyst question also what was the answer for the final temperature change i added 9 kelvin to 298 which is wrong so was it 298-9 or is that also wrong

Reply 2713

Anshul91

Original post by marleyxd

I wrote both for each reaction.. will i still get the marks?

no you have to write no equations

Reply 2714

Edmundith

Original post by MHay

If loads of people have written ionic equations they will probably accept it. The mark schemes are altered as they see what people write, so I presume that would be one that they would change into the mark scheme...

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.

Reply 2715

Divergent

Original post by yarshad

will you do the paper another time? or?

I'm not sure.
Probably looks like a gap year for me. :/
Oh well. At least I'm going to get better.

How was the paper?
Easy or hard?
I'd hope for hard because then it separates the good students from the great students..

Reply 2716

Jellydev

Original post by SuziieB

Guys I just calculated that I need 75 ums to get an A. What mark could that be??

(Please, be a C, please be a C...)

Posted from TSR Mobile

72ums to get a c. 55 marks
84ums gets a b. 63 marks

Based on last years exam boundaries! Will be similar

Reply 2717

erniiee

Original post by marleyxd

I wrote both for each reaction.. will i still get the marks?

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!

Reply 2718

username1054067

Original post by Divergent

Aw, get well soon :/

I found it quite difficult to be quite honest

Reply 2719

BobLoblawLawBlog

Original post by erniiee

Dunknoeee

77 - A*
70 - A
62 - B
54 - C
46 - D
39 - E

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

(edited 10 years ago)