F321 January 13th 2011: OCR Chemistry A Exam

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Reply 60

CassieB

Did anyone get the "Calculate the concentration of the hydroxide ions" question? :frown:

Reply 61

bashedup

Original post by pauljoseph

Ouch... there was a table? Where? I must've been more tired than I thought lol.

Me too!!! Duhhh.....
Looked it up when I got home and my lucky guess was right :smile:

Knew the first part OK but yep that second part was tricky cos they're so close.

Reply 62

TougherThanYSZ

Original post by CeeTay

did you manage to finish, does anyone know the worth of the final redox reaction q, and the question to put in the element on the last page as that is what i didn't manage to do ?

I rushed the Halogen halide question, probably got 4 marks out of 6. Then I had hardly any time to do the final page of questions. I could answer them, but alas not enough time so just did electron config' of gallium Q. The last page of Q's was 5 marks in total, 1 for the electron config' and 4 marks split between the rest (I could be wrong).

Reply 63

CeeTay

Original post by pauljoseph

i managed the electron config one as i figured i could do that in the final seconds over attempting the redox one, so thats 4 marks down the drain.. the rest I am unsure of AS I HAD NO TIME TO LOOK OVER!

Reply 64

Tateco

Original post by pauljoseph

Ouch... there was a table? Where? I must've been more tired than I thought lol.

About 2 inches up :wink:

Reply 65

bashedup

Original post by tateco

About 2 inches up :wink:

nooooo they actually gave it to you? I really rushed through reading some of the q's - that one obviously being one! I remember there being a table, but can't remember what else was in it other than the element names. Aaaargh!!! I went back to that EN q later and spent a good minute pondering the N-Br bit but never re-read the damn question. What an IDIOT!!! :mad:

Reply 66

TougherThanYSZ

Original post by tateco

About 2 inches up :wink:

Hahaha, wow... :insert:

Reply 67

Abused Tampon

hi can someone respond to this please.

for the question where it gave you two boxes and you had to draw a "dot and cross" diagram.... i got it all right, with the molecule letters with the right shape/electrons and everything, the problem is that i put the two diagrams in the oposite boxes. i didnt bother crossing it out and redoing it in the right box but i did leave a little note next to it saying "sorrying the the wrong boxes"

do you think that they will give me the marks for that question??

(edited 13 years ago)

Reply 68

TougherThanYSZ

Original post by Abused Tampon

Your guess is as good as anyones. Just keep your fingers crossed in the hope that a very nice person marks your paper. Out of curiosity, where did you leave the note? Because all exam papers are scanned into computers and marked online.

Reply 69

FadeOut101

yeah i got 2 for that Q as well, also what colour changes did ppl get for the 6 mark halogen Q (cant remember the Q exactly)?

Reply 70

nailclippers :S

Original post by FadeOut101

yeah i got 2 for that Q as well, also what colour changes did ppl get for the 6 mark halogen Q (cant remember the Q exactly)?

When it said Bromine water with Sodium chloride or what ever, I said there was no reaction as bromine is less reactive then chlorine therefore the organic solvent would go orange.
When added to the iodine one it would go purple.
With equations like
Br2 +2I- I2 + 2Br-

Reply 71

umzyy

Original post by sofiakousar

for the 2nd to last question about ocidation and reduction. between reaction
F2 + H2O= 2HF +1/2O2 what did people get for what was reduced and what was oxidised. i got F was from 0 to -2 and O2 was oxidised from -2 to-1 .
o ye and how did ppl balance it. im not sure if i got this right or not.

equasion unbalanced ao you would have lost a mark!!!!!

2F2+2h20>4HF+02

Oxidation Numbers
Flourine is an element so oxidation number is 0 then it bonds with H, therefore it has an oxidation number of -1. Flourine goes from 0>-1 so it reduced
Oxygen goes from -2>0 so oxidised.

hope that clears things up for you.

i found this exam really easy, and would be gutted if i dont get an A.

(edited 13 years ago)

Reply 72

KingofSpades

I thought there was some material which I would call "niche" for lack of a better word. It didn't seem to follow the usual format of questions, but rather seemed to pick up all the little bits that had been left out previous exams but are present in the text book. ie. Octahedral (never seen that on 1 paper before), the bit about neutralizing soil, how Van der Waals arise is also fairly rare.

Reply 73

TougherThanYSZ

Original post by KingofSpades

All were fairly rare in past exams, but all are definitely located in the text book indeed. Jan exams are for re-take students mainly, so it seems appropriate to avoid blatant past material.

(edited 13 years ago)

Reply 74

Oink123

What was the answer to that water of crystallisation question? It had like something012h12 so I got a bit confused.

Reply 75

KingofSpades

Original post by Heatheroink123

What was the answer to that water of crystallisation question? It had like something012h12 so I got a bit confused.

6

what's the difference between this exam and "salters OCR"?

Reply 76

hemcouture

Original post by tateco

About 2 inches up :wink:

Did you relise there was a last page I completely missed it coz Turn over was written in size 8 writing which was unfair!!!! :mad:

Reply 77

hemcouture

Original post by pauljoseph

That's a no go. It wouldn't get you anywhere, besides, if literally everyone struggled to finish with all the questions answered in depth, and correct, then the grade boundaries will be lowered accordingly. If not there is always May/June retakes.

I personally think an A in this paper will not be 80%- 48 marks, I reckon perhaps between 42 and 45 marks will get you an A, which was definitely doable (here's to hoping anyway).

I think its worth it or u could go with my complaint... i missed the last page indicated by size 6 writing (turn over) so i missed the last mark.
If u tell them timing was hard now theyll consider it 4 our next paper.
They can't guess?!

Reply 78

hemcouture

Original post by pauljoseph

All were fairly rare in past exams, but all are definitely located in the text book indeed. Jan exams are for re-take students mainly, so it seems appropriate to avoid blatant past material.

Yeah was stuff there never has been like HxA like A isn't even an element. we were never taught it. But Van der Waals formation was highlighted by OCR in the book as "Most candidates come into the exam not knowing this so make sure you do." The (OH) moles question was mean and do u know the answer to why less hydrogen being produced ...it was 1 mark but my chem teacher couldn't work it out!!!!