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OCR Chemistry A 2016 unofficial mark scheme 27/05/16

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Reply 120
Original post by jn998
This seems realistic. Did anyone keep a record of their multiple choice answers? I rushed through it and think I got quite a few wrong but I got: BDDCCCBDCBCBACBADBAD


I can't remember the order of my answers but I did recognise that the vast majority of my answers were B's in multiple choice..
Reply 121
On the isotope question can you write on the similarities that they react the same way nd difference that they can have different proporties???
Reply 122
Original post by LivToBe
In fact, one of the highest it has ever been is 83%...


One of the highest might have got 83%, but that happened recently I think. They cannot exceed 80% in our exams because we are doing the new specification and its the first year, which involves more content to remember for both of the exams.
A will probably be 53/54 which is roughly 75-77%.
Reply 123
Original post by 04hs02
On the isotope question can you write on the similarities that they react the same way nd difference that they can have different proporties???


Wasn't sure what it meant so said the similarities was same number of protons and difference was neutrons and mass
Reply 124
Original post by 04hs02
On the isotope question can you write on the similarities that they react the same way nd difference that they can have different proporties???


Similarities - same number of protons and having similar chemical properties

Differences - different number of neutrons and different masses is what they'll probably be looking for.
This guy is a teacher and will do the whole paper and post the mark scheme https://twitter.com/ChemistryALevel
Reply 126
Original post by oni176
Similarities - same number of protons and having similar chemical properties

Differences - different number of neutrons and different masses is what they'll probably be looking for.


I thought chemical properties were based on the electrons
Forgot what it meant by an homologous series -_-. Not sure I want to ruin my weekend by looking at the unofficial mark scheme. :ahhhhh::tongue:
Original post by Bosssman
It was Cr3Cl . 6H2O


It was CrCl3 6H20 btw
Original post by SGHD26716
I think there are always 20 marks available in MCQ. Shape around graphemes, I put tetrahedral.


I put trigonal planar. Due to the fact it has 3 bonded atoms and a lone pair - which against normal rules would cause it to be trigonal pyrimidal. However, graphene is one layer of graphite, therefore is planar. Due to its symmetrical nature and the fact that the lone pair, then becomes delocalised - hence why it gives graphene conducting properties - it had to be trigonal planar. Really funny question, would've caught a lot out.
Original post by jn998
I thought chemical properties were based on the electrons


It is based on electrons, an I sotope has the same number of electrons too.
For the question about "How can you make sure that all of the water of hydration has been removed?" or something like that - do you think they would accept adding cobalt chloride paper?
Original post by ComputeiT
For the question about "How can you make sure that all of the water of hydration has been removed?" or something like that - do you think they would accept adding cobalt chloride paper?


They'll be a few correct answers. Personally I just said heat for a longer period of time or calculate theoretical mass of water from an equation.
Original post by KevinClyde
They'll be a few correct answers. Personally I just said heat for a longer period of time or calculate theoretical mass of water from an equation.


Yeah hopefully - I left it out and came back to it at the end so just described that test for the presence of water and the observation!
Reply 134
Original post by adapttochangelad
It was CrCl3 6H20 btw


Yeah, sorry my mistake.
Reply 135
Original post by jn998
I thought chemical properties were based on the electrons


An isotope also has the same number of electrons too.
Original post by Bosssman
I used the periodic table value, I'm sure for that question they'll allow either as it didn't specify
I used it too, I'm got something like ....x10^-25 thou... might be wrong thou, I can't exactly remember what i put!
Does anyone remember the second multiple choice question? I'm pretty sure I got a B in that but on this thread people seem to have gotten a C/D?
I think the grade boundaries will be the same as usual. Even if it was an easier paper than previous papers you have to take into account that for us we have to learn everything whereas before the topics were split
Original post by RedRosesBloom
Does anyone remember the second multiple choice question? I'm pretty sure I got a B in that but on this thread people seem to have gotten a C/D?


https://twitter.com/ChemistryALevel

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