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Official AS OCR Chemistry A F321 Atoms, Bonds & Groups Jan Exam Thread Discussion :)

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Anyone have information on what to revise for the evaluative Task (OCR chemistry A), all I was told was:
You will be evaluating the preparation of an organic liquid??

Reply 781

kj14

Original post by hardz21

ok can someone explain this please, page 37 in the ocr textbook- question number 4c... what's the answer?

more so, how do you work it out... because the answer to biii) is 0.7 mol dm-3

and then in the answer thing on the exam cafe it says that

its 74.5 g mol-1 for the NaClO formula which is okay, but then it says to get the mass conc u have to do 74.5 x 0.7 which equals to 52.15

and then it says the answer is correct because it's 5.215 per 10ocm3

PLEASE EXPLAIN... this is just crazy :s-smilie:

Its Simple , your answer of 0.7 mol dm3 for biii is correct after that take conc is 0.7 mol dm3 this means there are 0.7 mole in a dm3 so you can write the equation
0.7=mass/74.5(molar mass of NaClO)
0.7 x 74.5 = 52.15g dm3
which is
5.215 g in 100cm3 , so is quite similar to the 4.5g per 100cm3 stated

Reply 782

Stuart W

Hey everyone :smile:

I have an As Chemistry qualitative exam tomorrow and I don't really know what to expect :/
I have been told it is about reactions of solutions and solids but that doesn't really give me any idea when it comes to preparation.
Any help would be much appreciated,
Thanks :smile:

Reply 783

Kitnimohabbathai

Original post by Stuart W

Hey everyone :smile:

I have a titrations practical next week but i think thats the quantitative exam...hope yours went well :smile:

Has anyone done the titrations practical? How did it go?

Reply 784

stateofdreaming

Original post by Kitnimohabbathai

I have a titrations practical next week but i think thats the quantitative exam...hope yours went well :smile:

Has anyone done the titrations practical? How did it go?

Ah, do you know what to revise? I'm really nervous about this titration because my pipette never fills up, ahah.

Reply 785

Alexandra's Box

Yay! My first post on an AS level exam thread :woo:

I like Chemistry. :biggrin:

We've got a bit of bonding and the groups 2 and 7 to do...

Reply 786

SchoolKid.

Just for anyone sitting this exam in January 2013 here is the thread for it -

http://www.thestudentroom.co.uk/showthread.php?t=2172419

Reply 787

spiderman2019a

Original post by Alexandra's Box

Yay! My first post on an AS level exam thread :woo:

I like Chemistry. :biggrin:

We've got a bit of bonding and the groups 2 and 7 to do...

and we are done yeah :biggrin:

Reply 788

spiderman2019a

Original post by Kitnimohabbathai

I have a titrations practical next week but i think thats the quantitative exam...hope yours went well :smile:

Has anyone done the titrations practical? How did it go?

mine too how are you revising?

Reply 789

spiderman2019a

Original post by stateofdreaming

Ah, do you know what to revise? I'm really nervous about this titration because my pipette never fills up, ahah.

hehehe why?? :confused:

Reply 790

spiderman2019a

Original post by thecdon

Hey guys,

I haven't noticed a thread for this exam, so I've decided to make one now :smile:

Is anyone sitting this exam for the first time? I'm on my gap year so have decided I may as well resit it!

just about to start my revision.

So everyone post in here!

If this thread becomes popular I may make other threads for other OCR A Chemistry exams this Jan.

so here is the NEWER version

feel free to join :smile:

http://www.thestudentroom.co.uk/showthread.php?t=2184418&p=40351075#post40351075

Reply 791

Kitnimohabbathai

Original post by librastar28

mine too how are you revising?

ohh sorry just saw this now...how did yours go? i just went over moles calculations and stuff...have you done the qualitative or evaluative yet?

Reply 792

Loiks94

last year boundaries where 50/60 for an A. Chemistry boundaries are always so high ffs

Reply 793

Alexandra's Box

Had a mock at college, got 62% as although I knew the answers the mark scheme is very specific. Did another mock at home and got 77% - yay certainly improving then! And we haven't actually been taught the Group 2 and 7 stuff, though quite a lot is basically what we have already done!

Reply 794

Chrissie2706

Page 36 question 2b(i) what analytical method is used to obtain this information?

Reply 795

aksahhafeez123

i did AS chem last year and got a B :/ im gna resit f321 paper and mark scheme could they please upload it on here i really wana see where i went wrong