A2 OCR Chemistry B F334 - June 2015

Lol! You're spot on.
And yes just doing exam papers right now. And youtube is currently my bestfriend for revision.
You?

on the page previously it said that polyesters could form hydrogen bongs so for I put that for PE as well as ID-ID and PD-PD

Myself I am just revising content mainly colours by design and the oceans topics then I'll hit as many past papers as possible, how are you feeling about F335?

I actually thought it was okay/decent and yes! I know everyone here is like 'it was ****, lets blow up OCR HQ' but I didn't think it was that bad certainly better than last years one that's for sure!

Are you revising for F335 now?

What I'm disliking at the moment is the fact that it's a PM exam (even though it gives us extra time to go over bits and bobs). I always feel sleepy during PM exams and my brain doesn't function properly. - This is just me moaning.

I'm also worrried I won't have enough time to look over my answers. I couldn't even afford to take a sip of water for this years F334 exam. I never run out of timefor exams but this year, I have.

I also wouldn't mind if the whole exam was just calulations. It would make my life easier.

SAME. Nothing can ever be as bad as last years paper

I do understand that but normally I wake up later to try and be relatively lively.
Yes! I went through the entire paper looked up at the clock was about to check my answers had 2 minutes remaining so it did go quicker compared to other exams.

Calculations are handy just some of the ones in the oceans do annoy me!

Anything you're finding a bit tricky?

We all came out last year's F334 shell shocked. For most of us the marks actually turned out okay. It was rogue and I'm surprised so many of you say it seemed like an easy past paper to do! I think the key with Salters is just respect the Storylines book and you'll be fine. All the rogue stuff is talked about in there - they never write on something which isn't in there. We then went in to F335 going '**** this better be nice', turned over page 1 and got raped again. I still ended up getting an A*, full in 334, lowish A in 335. Just because it's hard at the time, doesn't mean it won't turn out fine.

Yes. Its a fairly easy question about entropy calculation (ironic considering I wanted calculations to come up)

______________________________________________________________________
I'm so confused as to how the answer is -784

(ii) Usethe entropy data given in the table below to calculate the value of ∆Ssys (with the correct sign) for the forward reaction in the equation above

compound S/J K–1 mol–1
CH4(g) +186
H2O(g) +189
CO(g) +198
H2(g) +131

∆Ssys=_______JK–1 mol– [3] The answer for this is +216. It's the next bit I need help in

(iii) At 500 K the value of ∆Stot for the forward reaction is –1784.

Calculate the value of ∆Stot at 1000 K.

Assume that ∆Ssys does not change with temperature.

∆Stot =............................................JK–1 mol–1
[2]
_________________________________________
Sorry had to paste the whole thing. Not sure which past paper it's from.

Yes. Its a fairly easy question about entropy calculation (ironic considering I wanted calculations to come up)

______________________________________________________________________
I'm so confused as to how the answer is -784

(ii) Usethe entropy data given in the table below to calculate the value of ∆Ssys (with the correct sign) for the forward reaction in the equation above

compound S/J K–1 mol–1
CH4(g) +186
H2O(g) +189
CO(g) +198
H2(g) +131

∆Ssys=_______JK–1 mol– [3] The answer for this is +216. It's the next bit I need help in

(iii) At 500 K the value of ∆Stot for the forward reaction is –1784.

Calculate the value of ∆Stot at 1000 K.

Assume that ∆Ssys does not change with temperature.

∆Stot =............................................JK–1 mol–1
[2]
_________________________________________
Sorry had to paste the whole thing. Not sure which past paper it's from.

Hi, I did this question yesterday. If you don't mind me butting in!

The first thing is to calculate the enthalpy change of the reaction at 500K.

Delta S.tot. = delta s.sys + delta s.surr
-1784 = +216 + (-delta H/500K)
To rearrange all this you get delta H is -1,000,000

Then this is used to find the delta S.tot. at 1000K

delta S.tot. = +216 + (-1,000,000/1000)

Solving this gives -784.

Hi all,

I have finally managed to get hold of all of the June 2014 papers and I have created a zip folder containing them all.

Feel free to distribute them round.

Callum
https://drive.google.com/file/d/0B-EbxUSm2w_1X00yT2hRN0VvdFU/view?usp=sharing