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OCR Chemistry A Exam Thread (Breadth - May 27 2016 and Depth - June 10 2016)

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Original post by h3rmit


Lol I forgot to double the %error, gg me


Was it two marks or one mark? You usually get a mark if you wrote the correct equation. :smile:
Original post by Clintbarton
Same thing because they're both halogenation?


Yeah I think so:smile:
Original post by snickercell
But if low temp and high pressure push the equilibrium to the product/right hand side then surely that wouldn't produce a good percentage yield since more of the product would break down to form reactants?? There was a similar question in one of the specimen depth papers which is had a contradictory answer to the question in today's paper?image.jpeg


Ahh ok that's alright then, hopefully won't lose too many marks


I think you're misunderstanding equ. yield, if the equ. position shifts to the right you'll have more of the product (SO3) in the equ. yield, which is good
Original post by Clintbarton
Was it two marks or one mark? You usually get a mark if you wrote the correct equation. :smile:


just 1 in this case I believe
LMAO reading this I lost stupid marks. That big maths question on q=mcdeltaT ****ed me up i spent so long on it hahahhaha I'm gonna go before I doubt myself and cry. At least I got a week to make up for the revision of stuff that wasn't on the test.
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Original post by Clintbarton
Was it two marks or one mark? You usually get a mark if you wrote the correct equation. :smile:

1 mark
Original post by Firenze26
... I really don't know whether to be happy that the exam was relatively decent or scared by the fact that this will usually mean a high grade boundary.

Btw, do you guys know what reagent was used to add that oxygen in the second stage of prep in that last question?



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If you mean the last last question, you had to substitute hydroxyls in the place of halogens through nucleophilic substitution, you can't just add oxygens

Original post by Clintbarton
Was it two marks or one mark? You usually get a mark if you wrote the correct equation. :smile:

I think (read: hope) two marks
Original post by Clintbarton
Was it two marks or one mark? You usually get a mark if you wrote the correct equation. :smile:


1mark
Can some make a list of what came up so its easier to tell what we should revise for the next one?
Original post by A Sajid
Can some make a list of what came up so its easier to tell what we should revise for the next one?


it's probably best IMO to just go through everything, maybe a bit of practice on the maths things that didn't come up like pV=nRT as you don't want to regret a 6 marker on Le Chatelier's principle or something
Original post by Jitesh
it's probably best IMO to just go through everything, maybe a bit of practice on the maths things that didn't come up like pV=nRT as you don't want to regret a 6 marker on Le Chatelier's principle or something


I swear there was a 5 marker on Le chats today? the on about the temp and pressure
Original post by 87Mack
nah why do you square it? there was only one mole of SO3


It was two. I promise you.
Original post by 87Mack
concentration of S03 = 0.768 anyone????????


No.
[SO3]^2=0.786

Therefore

[SO3] = 0.887 moldm-3
Original post by A Sajid
I swear there was a 5 marker on Le chats today? the on about the temp and pressure


That's what I mean, they could give a 6 marker because everyone love's Le Chatelier! It's unlikely but who knows???
on one question i wrote CrCl2.6H2O for my answer by mistake, but in my working out I shown that it was CrCl3.6H2O. Would I lose a mark for this?
Original post by A Sajid
Can some make a list of what came up so its easier to tell what we should revise for the next one?


We didn't do any mechanisms therefore I think the following will come up:
-Mechanism(s) of any reactions
-Ozone depletion
-Group 2 and trends
-Analytical techniques e.g. MS, IR...

Any others?
Original post by Jitesh
That's what I mean, they could give a 6 marker because everyone love's Le Chatelier! It's unlikely but who knows???


You seem to have this under control. What textbook/ revision guide/ material did you use?
For the percentage error i said the answer was 2% as 0.005 is to 1 sig fig, will i lose a mark?
Original post by Major Wilson
We didn't do any mechanisms therefore I think the following will come up:
-Mechanism(s) of any reactions
-Ozone depletion
-Group 2 and trends
-Analytical techniques e.g. MS, IR...

Any others?


That Polymer sh** also?
Original post by Major Wilson
We didn't do any mechanisms therefore I think the following will come up:
-Mechanism(s) of any reactions
-Ozone depletion
-Group 2 and trends
-Analytical techniques e.g. MS, IR...

Any others?


-Types of bonding e.g London forces
-History of the periodic table
-Catalysts
-Polymers

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