Edexcel A2 Chemistry 6ch04/05 JUNE 2015 Watch

Hairysweets
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#1261
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#1261
I did the 79% yield one like this:

100 Sodium Theoxide(?) (Mr =116) made 79 Asprin (Mr = 180)

Therefore, 100 x 116 in relative weight made 79 x 180.
11,600 made 14,220

14,220 was bigger than 11,600. The ratio of 14,220/11,600 multiplied by 2.5 tonnes gave you the value.

Reasoning: every 1/11,600th of a weight will give you 14,220. I got an answer of 3.06... which rounded to 3.1 for the 2sf specification.
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MoHoosen9167
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#1262
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(Original post by frozo123)
yeah did you get 1.8-3.0 for the other one?
C=C for the diminishing one?
and OH in carboxylic acids for the appearing one?
k=0.21
KOH used for transest one?
I can't remember what I put for the appearing one, Idek if I put COOH or not I may have. But I messed up my rate equation - got 3/5 marks on that. And therefore my k was incorrect, but I would have got ECF apart from on the units.
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DCMed96
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#1263
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(Original post by MoHoosen9167)
We were already given the 0.1-1.9

My second one was 1.8-3.0
(Original post by Wahid1)
That and 0.1-1.9 yeh


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thought would be higher than 0.1 becuase it is Ch2, and not Ch3, so will be higher ..m(i put 0.2-1.9) will they accept that
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frozo123
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#1264
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(Original post by DCMed96)
thought would be higher than 0.1 becuase it is Ch2, and not Ch3, so will be higher ..m(i put 0.2-1.9) will they accept that
I think it was 1.8-3.0
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ojstratton
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#1265
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(Original post by Wahid1)
Grade boundary predictions:
A: 60
B:54
C:48

How much more unorthodox can a paper get?!?

Thank you Edexcel for recruiting Satan as the author for Unit 4.


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A little but cruel to the examiner. Previous Edexcel chemistry grade boundaries have been annoyingly high in previous years (think about unit 1 last year - the paper was rather straight forward that mean you lost more UMS for simple mistakes). If the grade boundaries are lowered for this paper, it will hopefully mean simple mistakes in easy questions won't effect the UMS that much
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HappyCheesecake
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#1266
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#1266
(Original post by frozo123)
should do
Thanks
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Amanda Brown
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#1267
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#1267
Any chance of in unofficial mark scheme?
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noorjamal
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i explained that B was zero order and X was first order but i didnt include B as zero order in my overall rate equation, do you think ill still get the mark?
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Wahid1
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#1269
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#1269
(Original post by frozo123)
I think it was 1.8-3.0
Nah same halos liane group so same


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Hairysweets
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#1270
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(Original post by MoHoosen9167)
I can't remember what I put for the appearing one, Idek if I put COOH or not I may have. But I messed up my rate equation - got 3/5 marks on that. And therefore my k was incorrect, but I would have got ECF apart from on the units.
I put C=C going but C=O forming as they might say O-H could be present in OH? That's my only reasoning for me personally not putting it.

I've seen in past papers you get penalised for any extensions on the 2 bonding atoms in context, e.g. -C-OH would lose you the mark instead of O-H. Even -O-H would lose you the mark! And sorry, realise I replied to you instead of your quote!
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frozo123
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(Original post by noorjamal)
i explained that B was zero order and X was first order but i didnt include B as zero order in my overall rate equation, do you think ill still get the mark?
But A was first order
so your rate equation should be
Rate=k(A)(X)
k=0.21 mol^-1dm^3s^-1
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Wahid1
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(Original post by Wahid1)
Nah same haloalkane group so same


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frozo123
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#1273
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(Original post by Wahid1)
Nah same halos liane group so same


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but if you look in the nmr table the C was attached to a C with double bond O
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Supra123
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#1274
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(Original post by noorjamal)
i explained that B was zero order and X was first order but i didnt include B as zero order in my overall rate equation, do you think ill still get the mark?
Yeah you do
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blueynuey1
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#1275
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Please vote on difficulty here:

Poll: http://strawpoll.me/4593433
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egggirl
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#1276
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(Original post by noorjamal)
i explained that B was zero order and X was first order but i didnt include B as zero order in my overall rate equation, do you think ill still get the mark?
yeah thats fine
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Hairysweets
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#1277
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(Original post by noorjamal)
i explained that B was zero order and X was first order but i didnt include B as zero order in my overall rate equation, do you think ill still get the mark?
Yeah you will going off of mark schemes. I saw once they said 'ALLOW [A]^0', so I think they expect you to not include it
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MoHoosen9167
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#1278
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So I used the enthalpies of formation instead of their reverses, so I would have lost marks on that. And then I would have lost marks on calculating the enthalpy change for the reaction. Then I would have lost marks on ∆Ssur. Then I would have lost marks on ∆Stot. And then the succeeding question.
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Nautic4l
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#1279
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(Original post by Callum_Stewart)
did you divide the number of moles you had by the new volume, 65cm^3?
Damn I wasn't sure whether I should do that!! But then did you do the KW thing yeah? Hopefully I get ecf or something lol :/

And what did people get for part b of the N2O4 mcq?
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frozo123
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(Original post by MoHoosen9167)
So I used the enthalpies of formation instead of their reverses, so I would have lost marks on that. And then I would have lost marks on calculating the enthalpy change for the reaction. Then I would have lost marks on ∆Ssur. Then I would have lost marks on ∆Stot. And then the succeeding question.
if your examiner isn't lazy he should work out whether what you do was correct from your incorrect place lol
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