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

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Reply 520
Avatar for S.G.
S.G.
22
Original post by MiracleLeaf
Same! I've finally found someone who got the same! :P


The correct answer was 300 as there were two gases and you had to add their volumes
Reply 521
Avatar for S.G.
S.G.
22
Original post by 11234
So what are unid like Cambridge gonna do if theres no ums? Are they going to look at raw mark?


Admissions test and just use your raw mark. I quite like showing the raw marks so you can see exactly how you did and if you need to remark immediately.
Original post by SGHD26716
The correct answer was 300 as there were two gases and you had to add their volumes


Fml I didn't clock there were two gases :frown:
I reckon it'll still be around 73 ish% for an A
Reply 524
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S.G.
22
Original post by therealbatman365
Fml I didn't clock there were two gases :frown:


I didn't realise that at first either and put 60 after working out one. But later while checking realised there was oxygen as well.
Reply 525
Avatar for oni176
oni176
7
I think I've got around 50-52 marks. What grade do you reckon that is?

This is a new specification, so I am not expecting high marks in this.
Original post by SGHD26716
The correct answer was 300 as there were two gases and you had to add their volumes


Yes I know. That's what I put. It's because of the molar ratios, right?
Original post by medicapplicant
ImageUploadedByStudent Room1464422133.763161.jpghow did you all do this question and what was your answer
Part c btw
I did 0.15/(45/1000) and got 3.33
Would that be right

Posted from TSR Mobile


I calculated mole ratio and the minimum concentration needed (3)!and since he had 10% more, I did 1.1*3 which is 3.3
Reply 528
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11234
8
Original post by SGHD26716
Admissions test and just use your raw mark. I quite like showing the raw marks so you can see exactly how you did and if you need to remark immediately.

But raw marks arent the same as ums so say aqa chemistry could be hqrder than ocr this year but getting a 45 on both would be viewed the same
Reply 529
Avatar for S.G.
S.G.
22
Original post by 11234
But raw marks arent the same as ums so say aqa chemistry could be hqrder than ocr this year but getting a 45 on both would be viewed the same


So, say both exams are out of 70 marks and AQA is harder than OCR. Then the marks for an A in AQA would be lower than OCR.

The key thing you have to remember is that this is now a stand alone AS. It doesn't affect your final A2 grade. So, you would get your grade based on raw marks.
Original post by SGHD26716
3.33 is correct. I said 90% is 0.15 moles. So 100% is 1/6 moles and then just worked it out as normal


so volume affects concentration?
Reply 531
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S.G.
22
Original post by simply_a_ Δ
so volume affects concentration?


moles=concentration * volume

concentration=moles/volume

Of course volume affects concentration, look at units, mol per dm3
Original post by SGHD26716
moles=concentration * volume

concentration=moles/volume

Of course volume affects concentration, look at units, mol per dm3


I was under the impression that concentration decreases if you dilute something with water.
Silly me.
Cheers matey!
Original post by simply_a_ Δ
I was under the impression that concentration decreases if you dilute something with water.
Silly me.
Cheers matey!


Concentration does decrease.. If you add water the volume increases and moles stay the same so concentration therefore decreases
Original post by marioman
There is no UMS as this is a linear specification. You will just get a raw mark (your total over both papers) and a grade.


Is it confirmed that raw marks will be reported on our results sheet?
Original post by WhyAlwaysMe?!
Is it confirmed that raw marks will be reported on our results sheet?


I don't think it's confirmed but I expect that they will (when I took linear GCSE mathematics they did). If not you can always get them from your teacher/exams officer.
Reply 536
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11234
8
Original post by SGHD26716
So, say both exams are out of 70 marks and AQA is harder than OCR. Then the marks for an A in AQA would be lower than OCR.

The key thing you have to remember is that this is now a stand alone AS. It doesn't affect your final A2 grade. So, you would get your grade based on raw marks.

But then to what degree do you advantage a candidate like before cambridge looked for above 90/95 ums as ums was a decent comparative method but now you cant really set a threshold to what youre looking for so maybe they have changed to raw marks but I dont see that working. Like they may both be As but what type of A because ums isnt linear
Reply 537
Avatar for S.G.
S.G.
22
Original post by 11234
But then to what degree do you advantage a candidate like before cambridge looked for above 90/95 ums as ums was a decent comparative method but now you cant really set a threshold to what youre looking for so maybe they have changed to raw marks but I dont see that working. Like they may both be As but what type of A because ums isnt linear


I don't know
Original post by 11234
But then to what degree do you advantage a candidate like before cambridge looked for above 90/95 ums as ums was a decent comparative method but now you cant really set a threshold to what youre looking for so maybe they have changed to raw marks but I dont see that working. Like they may both be As but what type of A because ums isnt linear


I think the answer is that you don't. Cambridge are introducing new Admissions Assessments for 2017 entry which will replace the role of UMS.
Original post by ComputeiT
The ocr textbook page 120 says that silver sulfate is insoluble so shouldn't that multiple choice question be D - effervescence and precipitate?


exactly thats what i thought but that chemistry teacher who uploaded the test said there was no precipitate either :/ i hope they give the mark either way although i doubt they will

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