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OCR B F335 - Chemistry by Design - 13th June 2012

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I found it hard, really.
But surprisingly I got the "suggest the structure" drawings correct.
What did you guys put on the question of decomposition of ZnCl2.2H2O?

I put ZnOHCl.H20 - but I always get those things wrong

But on another note... I dreamt about this exam last night, FML, I vividly remember the structural formula of methanal coming up... :mad:

Edit: googled it - found the answer, it's on here

http://portal.acs.org/preview/fileFetch/C/CNBP_029702/pdf/CNBP_029702.pdf

it goes to ZnCl(OH) + HCl + H2O

I'm just saying - if I could've had google in that exam i'd have aced it... Fail...

(edited 11 years ago)

Reply 1241

lightray

I googled it too I dont think it is something that a A2 student knows, as well as the drawing. Well I really think that any sensible alternatives could get the marks.
I put ZnCl.2H2O ----> HCl + HOCl + Zn + H2O, dont think i will have both marks

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Reply 1242

Hasi.ali

Original post by DipolarBitch

What do you call a clown in jail?

A Silicon.

Ur not funny.

Anyone got the exam!

can anyone explain how u were supposed to find the concnetration of Nitrogen using the Oxygen concentration?

And then for the ratio question what did people get?

I got 7.14 But I didnt write that and for some reason wrote 7:1 :s-smilie:

(edited 11 years ago)

Reply 1245

Princess Kawaii

Isn't anybody putting a mock mark scheme together?

Reply 1246

misspinx20

Original post by SimpleGirl

I got this too.. :unsure:

This paper was beyond difficult.
I honestly felt that I had revised enough to do well but the questions were just ridiculous.

EDIT:

Oh great :facepalm:

:O what?! But how you meant to realise that in an exam situation :frown:

Has anyone made an unofficial mark scheme yet?

Reply 1247

Birterillo

Original post by InkyOne

I put ZnOHCl.H20 - but I always get those things wrong

But on another note... I dreamt about this exam last night, FML, I vividly remember the structural formula of methanal coming up... :mad:

I did the same as you. I think we'll have got at least 1 mark because all we did was .H20 instead of +H20. Not a massive error really. May even be exchangeable...

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Reply 1248

suggsina

Original post by Toshiya

I thought it was C4H8O4?

I can't say for sure but i remember thinking the lactic acid had been doubled up. Oh well, good luck anyway :smile:

Reply 1249

Toshiya

Original post by suggsina

I can't say for sure but i remember thinking the lactic acid had been doubled up. Oh well, good luck anyway :smile:

It might have been, I might have drawn it with 6 carbons haha... I can't remember!

Reply 1250

Alex J

Original post by InkyOne

I put ZnOHCl.H20 - but I always get those things wrong

But on another note... I dreamt about this exam last night, FML, I vividly remember the structural formula of methanal coming up... :mad:

I reckon what you put may actually get you the marks. It will probably say:

ZnCl(OH) + HCl + H2O

in the mark scheme, but it would probably also say "Allow ZnClOH.H20". Also, I don't think the brackets are important, for the same reason you write NaOH instead of Na(OH).

Reply 1251

InkyOne

Original post by suggsina

I can't say for sure but i remember thinking the lactic acid had been doubled up. Oh well, good luck anyway :smile:

It was - lactic acid has 3 carbons, one with the carboxylic acid group, one attached to the OH and a methyl group on the end :smile:

Reply 1252

InkyOne

Original post by Alex J

Here's hoping! :smile:

Reply 1253

Princess Kawaii

what was the question and answer for the last question about solubility?

Reply 1254

InkyOne

Original post by Princess Kawaii

what was the question and answer for the last question about solubility?

Along the lines of does solubility increase of an ionic solid who's dissolving is endothermic, at higher temperatures.

the answer was yes, because it makes the negative value of delta S surroundings tend towards 0, so increasing the value of delta S total, and increasing the likelihood of the solid dissolving spontaneously.

Reply 1255

Dixie

so is everyone thinking that the grade boundaries will be low for this like 81 and below?

Reply 1256

Einy

I thought it was way easier than f334 in january, just a shame the maths ones i had today didnt go so well - edexcel clearly wanted to get us back for their easy jan papers