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Reply 420
Original post by ngullan
Does anyone have the paper from january 2013?

Also, any ideas on how I can fully understand electrophilic/nucleophilic addition? I've spent loads of time on it, and I think I understand how they differ, but I always lose marks for the reaction mechanisms.


In Electrophilic addition the double bond in alkenes break and the compound it reacts with joins on- hence the addition of electrons
In Nucleophilic Substitution the compound replaces it and involves halogenoalkanes e.g the -Br gets replaces by -OH- hence a nucleophile substitutes its self!

electrophilic addition- http://www.chemguide.co.uk/mechanisms/eladd/whatis.html#top
nucleophilic substitution- http://www.chemguide.co.uk/mechanisms/nucsub/whatis.html#top
Reply 421
Sulphur or Sulfur? I prefer Sulphur :frown:.

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Reply 422
Original post by Branny101
Sulphur or Sulfur? I prefer Sulphur :frown:.

Posted from TSR Mobile


My teacher said you wouldn't get penalised for writing sulphur, but i'd still write sulfur to be on the safe side (you never know with OCR) :tongue:
(edited 10 years ago)
Reply 423
Original post by super121
My teacher said you wouldn't get penalised for writing sulphur, but it still write sulfur to be on the safe side (you never know with OCR) :tongue:


Good point :smile:

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How does everyone feel about the exam?
Guys there is a question in the may 2012 paper which i dont understand where ive gone wrong in

question 1b in the june 2012 paper. i dont see how its c15h22o??

i keep counting 20 or 21. can somebody please explain properly to me?
Original post by NielsBohrsDad
Guys there is a question in the may 2012 paper which i dont understand where ive gone wrong in

question 1b in the june 2012 paper. i dont see how its c15h22o??

i keep counting 20 or 21. can somebody please explain properly to me?


Oooh I did this question and at first I got that too, but then I literally drew out all the bonds on the diagram, okay, let me do that for you now and take a picture okay?
Reply 427
Original post by Whostolemycookie
How does everyone feel about the exam?


Okay, but with advance notice questions who knows what comes up and you cannot really prepare much for them :frown:
Original post by NielsBohrsDad
Guys there is a question in the may 2012 paper which i dont understand where ive gone wrong in

question 1b in the june 2012 paper. i dont see how its c15h22o??

i keep counting 20 or 21. can somebody please explain properly to me?


Okay here you are! I've drawn on all the hydrogen bonds, I'm sorry the quality is quite bad and I had to rub out all the previous bonds I'd drawn, so just look at the ones in black
Original post by nukethemaly
Oooh I did this question and at first I got that too, but then I literally drew out all the bonds on the diagram, okay, let me do that for you now and take a picture okay?



thanks mate. i just really wanted to know where i was going wrong cos these questions actually carry on and you lose marks when using the formula later.

so i want to be able to apply itlike that in the exam.
Original post by NielsBohrsDad
thanks mate. i just really wanted to know where i was going wrong cos these questions actually carry on and you lose marks when using the formula later.

so i want to be able to apply itlike that in the exam.


Yeah no, of course I understand :smile:

I've attached how I do it btw!

Good luck tomorrow
Reply 431
Original post by NielsBohrsDad
Guys there is a question in the may 2012 paper which i dont understand where ive gone wrong in

question 1b in the june 2012 paper. i dont see how its c15h22o??

i keep counting 20 or 21. can somebody please explain properly to me?


http://www.thestudentroom.co.uk/showthread.php?t=2349586&p=42591735
Original post by Whostolemycookie
How does everyone feel about the exam?


I'm actually quite prepared, other than the advanced notice and just some revision here and there. I'm going to spend the day going through the advanced notice, gonna summarise each paragraph and come up with questions they can ask there. And after that I'm gonna go through the specification once more.

How are you feeling about it?
Reply 433
Can someone please answer my question

How do I know whether I should put state symbols in a reaction?

Do I just assume they are not needed unless asked for?

Thanks
Original post by krisshP
Can someone please answer my question

How do I know whether I should put state symbols in a reaction?

Do I just assume they are not needed unless asked for?

Thanks


they ask for it, but for ionic equations I would always put them on regardless.
Reply 435
Original post by nukethemaly
they ask for it, but for ionic equations I would always put them on regardless.


:biggrin: thanks
Original post by krisshP
:biggrin: thanks


How are you feeling about it?
Original post by nukethemaly
x


Not to well tbh, I'm really tired and so I'm gonna revise for a bit and wake up at 2am and do more work :smile:
Also how did you do the question before, how do you know where the hydrogen bonds are?
(edited 10 years ago)
Reply 438
Original post by nukethemaly
How are you feeling about it?


For the first 4 questions I think out of the 80 marks for them I'll do okay and drop like 5 marks so long as no stupid mistakes occur, paper is not weird like our unit 1 physics one and mark scheme does not change. But then the advance notice Q5 questions will be annoying and a bomb :frown: and I'll probably loose at max 10 marks :frown:

You?
Reply 439
This advance notice idea for an exam totally sucks IMO! It allows OCR to be have a 'unique' spec, but it totally rubbish and so hard for us! :frown:

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