ocr a f325 revision thread

Reply 3540

MathsNerd1

17

Original post by Benjy100

Kc 16.8? (3s.f.)

Buffer solution pH of 3.99 or something? o.O

I got all this so hopefully it's all correct! :biggrin:

Reply 3541

LawApp2013

HATED THAT EXAM!!!!!!!!!! thought it was harder than JAN 13 tbh, luckily need a 93 ish/150 to get an A, but there goes the A* :frown:

Reply 3542

TauMuon

10

I thought this paper was definitely challenging; a lot of places to slip up. Definitely much harder than June 12 which was a breeze by comparison. I personally thought Jan13 was more straightforward than this, so my prediction is mid-low 70s for an A, maybe 73? Anyway...

I got NiSO4.7H2O for the formula of the hydrated salt.

I got FeO4^2- for the ferrate ion (think I missed out the '2-' though :s-smilie:

)

I got 3.12 x 10^14 g for the mass of CO2

3.99 for the buffer

13.6 for the alkali pH

4.14 for the weak acid pH

16.8 (think it was no units? Can't remember) for Kc

-3454 kJmol^-1 for lattice enthalpy

I completely missed the 4 marker to do with chlorine :/

Reply 3543

georgiaaaxo

8

how on earth did people think this went well!?! omg it was awful for me, looks like I'm not going to uni :frown:

Posted from TSR Mobile

Reply 3544

zef1995

10

Original post by Benjy100

Kc 16.8? (3s.f.)

Buffer solution pH of 3.99 or something? o.O

Oh my goodness I got both of those answers! :biggrin:

Reply 3545

username938518

1

Original post by massi1296

anyone got the paper they can post up??
anyone get somethign like 1.17x10^somethign 15-20 grams for the co2 mass

I cant remember the number I got but I got it to 10^17

Reply 3546

keepontrying

Original post by MathsNerd1

I got all this so hopefully it's all correct! :biggrin:

I got this too

Reply 3547

LawApp2013

Original post by MathsNerd1

I got all this so hopefully it's all correct! :biggrin:

Atleast I got these right too

Reply 3548

Better

8

Original post by talliehughes

I got NiSO4.7H20 too! I worked out the 7 waters bit, but I'm going to be honest, I completely gussied the sulphate bit. I figured if nickel had a +2 charge then the ion making the salt would have a 2- charge, but adding the molar mass in the end gave me the right number of moles :smile:

I don't think I'll get all the marks on that as I didn't fully work it out, some of it was a guess.

Also, what did everyone get for the kc?

So annoying. I was on AQA for Chem 1 and Chem2.

We never did this Water of Crystallisation bullshxt, pardon my French.

This is ridiculous they should have just given a bog standard titration question.

Reply 3549

talliehughes

Original post by keepontrying

what was everyones KC value?

I got 16.75

Reply 3550

NerdMeister

That exam sure was pretty damn difficult! There were a few questions that I had to guess for but it looks like I got similar answers to other people for the longer calculations so that makes me a bit happier :smile:

Did other people get 3.99 for the pH of the buffer solution? I got NiSO4 like a lot of other people here for the last question but I didn't include the water of crystallisation, I didn't think we had to :s-smilie:

Reply 3551

MathsNerd1

17

Original post by Better

Lol Maths nerd you're supposed to be off the studentroom.

Fortunately yesterday I went over the Jan13 buffers question with my teacher.

You work out mols before
Mols used and then the conc of the HA and A-

Lowest I got on that Paper was 80. I don't like to say this but I really hope because it's June with fewer prepared students that will push my UMS pretty high.

Yeah, so are you though :tongue:

I just needed to check it out really and well I think I've gotten about 85 if not maybe a bit more. Definitely not too bad of a paper but you definitely had to know your stuff for it :smile:

Reply 3552

ah1189

thinking practically, i don't think grade boundaries will be that low, compared to past papers it wasn't that hard. The last question was hard, but compared to some past ones, it wasn't that bad :smile:

personally only got lost on a few small parts. the born-Haber question was easiest one they've ever asked, hopefully lowish grade boundaries, but personally don't see it

Reply 3553

keepontrying

Original post by zef1995

Oh my goodness I got both of those answers! :biggrin:

I got this too!

Reply 3554

georgiaaaxo

8

fml I can't stay on here and realise I got even more than I thought wrong :frown:

actually feel like crying it was just terrible. going to pray for a miracle!

Posted from TSR Mobile

Reply 3555

jess_m94

12

Original post by Benjy100

Kc 16.8? (3s.f.)

Buffer solution pH of 3.99 or something? o.O

I got that for Kc. Can't remember what pH I got but my friend got 3.99. I think I did that one wrong because I'm pretty sure I didn't get it :frown:

Reply 3556

Dursty

10

Ffs i did the hard part but forgot the 7 water of crystallisation! There goes 2 marks or so

Reply 3557

Better

8

Original post by TauMuon

I thought this paper was definitely challenging; a lot of places to slip up. Definitely much harder than June 12 which was a breeze by comparison. I personally thought Jan13 was more straightforward than this, so my prediction is mid-low 70s for an A, maybe 73? Anyway...

I got NiSO4.7H2O for the formula of the hydrated salt.

I got FeO4^2- for the ferrate ion (think I missed out the '2-' though :s-smilie:

)

I got 3.12 x 10^14 g for the mass of CO2

3.99 for the buffer

13.6 for the alkali pH

4.14 for the weak acid pH

16.8 (think it was no units? Can't remember) for Kc

-3454 kJmol^-1 for lattice enthalpy

I completely missed the 4 marker to do with chlorine :/

You are an absolute freak of nature,jesus christ.

Reply 3558

LawApp2013

Original post by TauMuon

I thought this paper was definitely challenging; a lot of places to slip up. Definitely much harder than June 12 which was a breeze by comparison. I personally thought Jan13 was more straightforward than this, so my prediction is mid-low 70s for an A, maybe 73? Anyway...

I got NiSO4.7H2O for the formula of the hydrated salt.

I got FeO4^2- for the ferrate ion (think I missed out the '2-' though :s-smilie:

)

I got 3.12 x 10^14 g for the mass of CO2

3.99 for the buffer

13.6 for the alkali pH

4.14 for the weak acid pH

16.8 (think it was no units? Can't remember) for Kc

-3454 kJmol^-1 for lattice enthalpy

I completely missed the 4 marker to do with chlorine :/