Ocr f321 23 may 2013~official discussion thread

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OH MY GOSH! IT'S OVER.

Thats the 3rd time i've taken that exam, for the love of god, I am never doing it again.
Does anyone have an unofficial mark scheme floating around?

Plus what did you get on the water of crystallisation question?

Hope it all went well for youuuu!!!!!!

x was 16. Are you doing A2?, if so how are you feeling for the F325 OR F324 exam?

Reply 1241

jackitsme

Original post by Nermin Hayek

Oh really ? even if they asked us to show outer shell electrons? That's a relief :smile:

oh fudge did they? i dont recall that :frown:

! damn 1 mark only out of 2 then
funny **** with the sarcasm.:L

Reply 1242

drplease

Original post by Zakee

The question was testing your understanding that you can have moles of anything (in response to the previous poster before you).

I think, (from memory), you had something like this:

Number of moles = m/RMM

Number of moles = 0.05 moles.

0.05 x 6.02 x 10^23 = 3.01 x 10^22 molecules.

you then times it by 5 as there are 4 Cls and 1 Si..... got the PH3 one wrong, where i put Vdw, got the litmus paper things wrong prob.. overall speaking as a A2 student, the paper was comparatively harder than previous papers. Some principles I have a feeling some may find hard to integrate, as F325 (A2 unit) helped out in the calculations.

Reply 1243

JoshBridgett

Original post by Char-

Hopefully you did well this time :smile:

The answer to the water of crystallisation was 16 I believe :smile:

Reply 1244

Nermin Hayek

Original post by jackitsme

yup because its a full shell so no point showing the rest,BOTD(benifit of the doubt woud be given)

I hope so but what would the other mark been for other than the dative covalent bond between b and n ?

Reply 1245

gaby_xo

Original post by jackitsme

there was no bonding and structure,many failed to read it was about IE of the LI,C and F

so its about shells ect

I'm so happy I read that one twice. I definitely wrote about ionisation energy going up across the period because increasing nuclear charge that increases the spun clear attraction to the outer most electrons, reducing the atomic radius, which increases the over nuclear attraction causing an increase in first ionisation energy :confused:

Reply 1246

Ché.

Original post by jackitsme

yeah the ionisation one you talk about ionisation energy -shells,nuclear charge ,cmon???? why would you talk about structure and bonding :L

I was referring to the wrong question, which I already pointed out.
I did converse on the topics that you mentioned so everyone's cool!

:biggrin:

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(edited 10 years ago)

Reply 1247

Moon1ight

Does the dot formula number show you the number of water molecules in the compound ?

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Reply 1248

Nermin Hayek

Original post by krishkmistry

Does the dot formula number show you the number of water molecules in the compound ?

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Yh the waters of cyrstallisation present

Reply 1249

Munrot07

anyone got a copy of the paper? I didn't do this paper but would like to see it to see how it was :smile:

Reply 1250

gaby_xo

Original post by Nutter95

I ballsed the group 2 question up too...panicked and changed my answer three times. ultimately to the wrong answer aha.

I just had 3 minutes left and I couldn't think what the hell it was on about
Grr I'm so angry at myself, that's 5 marks down the drain :frown:

Reply 1251

Ché.

Original post by gaby_xo

I just had 3 minutes left and I couldn't think what the hell it was on about
Grr I'm so angry at myself, that's 5 marks down the drain :frown:

You didn't get to answer it?!

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Reply 1252

username571327

i think ive lost around 5/6 marks, hopefully boundaries wont be too high

Reply 1253

DefaultSkin

Anyone got an unofficial mark scheme and what do you reckon the grade boundaries are going to be like??

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Reply 1254

gaby_xo

Original post by Ché.

You didn't get to answer it?!

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I did do it.. I just wrote a rubbish answer that made no sense at all
And it was completely wrong..
I'm so annoyed cause I really need an A in this :-(

Reply 1255

Zakee

Original post by drplease

It asked for the number of molecules. Not the number of atoms. SiCl4 is the molecule. The number of atoms are (x5) greater than the number of molecules.

Reply 1256

Annie_o

Would I get the mark for concentrated ammonia 'solution' and not just concentrated ammonia?

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Reply 1257

ChestnutHero

For the question about further testing halogens/precipitates do you think putting 'aqueous ammonia solution' would be enough or do you HAVE to put 'concentrated' too?

Reply 1258

Nermin Hayek

Original post by ChestnutHero

For the question about further testing halogens/precipitates do you think putting 'aqueous ammonia solution' would be enough or do you HAVE to put 'concentrated' too?

I wrote that too but I think we should have mentioned concentrated :frown:

Reply 1259

Regina15

Original post by Ferrari_1996

I remember getting 360cm3 for a question. I think you got 360 and multiplied it by 3 but I think you had to multiply by 3 before, not in the end. I hope someone can clarify this.