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OCR AS - Chemistry Unit F322 - Chains, energy and resource - REVISION!

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Reply 360
Avatar for lucy1234
lucy1234
grade boundaries for A?
Quick question, would you lose marks for writing Ea instead of activation energy?
Original post by touran22
thats what i thought the overall equation was...can some one please clarify!

and yes The rate or formation of ozone = The rate of decomposition <----- this statement is for o3+o--->2o2


Markscheme accepts:

O3 + O ---> 2O2
2O3 ---> 3O2
How do you draw the skeletal formula for E/Z isomers? and how do you know how to change what?
Reply 364
Avatar for Flint_09
Flint_09
8
someone plz help with this 1 mark question. JUNE 2010 F322 PAPER

how do u do 6 c (i). i know it must be easy as it is only 1 mark but i don't get it.

http://www.ocr.org.uk/download/pp_10_jun/ocr_57549_pp_10_jun_gce_f322.pdf
Original post by Flint_09
someone plz help with this 1 mark question. JUNE 2010 F322 PAPER

how do u do 6 c (i). i know it must be easy as it is only 1 mark but i don't get it.

http://www.ocr.org.uk/download/pp_10_jun/ocr_57549_pp_10_jun_gce_f322.pdf


(2.5 x 10^5) x 4 (as there are 4 moles of NO) x -909kJmol^-1
GUYS!!!???? can i use the term Ea in answers instead of writing activation energy? or will they deduct marks?
Reply 367
Avatar for shuty
shuty
9
Original post by EternalDoom
Quick question, would you lose marks for writing Ea instead of activation energy?


NOO
Reply 368
Avatar for shuty
shuty
9
Original post by croag
FML, done no revision. What's the likelihood of me getting at least 70% (gotta get this to get an A) if I start now? :smile:


Depends on what u already know mate
Reply 369
Avatar for shuty
shuty
9
Hey guys... what do u think might come up?
Do you have to draw dots on your radicals or not

also, when do you draw these dots

some mark schemes take away marks for drawing dots on radicals, some penalise you for not drawing them

what!
Original post by EternalDoom
Markscheme accepts:

O3 + O ---> 2O2
2O3 ---> 3O2


How do you draw the skeletal formula for E/Z isomers? and how do you know how to change what?
Reply 372
Avatar for bagelbe
bagelbe
I don't understand why people are saying past papers don't prepare you for the exam??? :/
Original post by bagelbe
I don't understand why people are saying past papers don't prepare you for the exam??? :/


THEY DO

but examiners always come up with rubbish random questions
Reply 374
Avatar for bagelbe
bagelbe
Original post by sixthformer
THEY DO

but examiners always come up with rubbish random questions


Yeah, I blame OCR because they always seem to take a bit from the book that is really small part of it and then write a 6 mark question on it >:frown:
Reply 375
Avatar for bagelbe
bagelbe
Original post by lucy1234
grade boundaries for A?


Varies between papers, but I'd say between 75-80%?
Original post by sixthformer
THEY DO

but examiners always come up with rubbish random questions


Salaam bro could you help me please

How do you draw the skeletal formula for E/Z isomers? and how do you know how to change what?
Original post by High VOLTAGE
How do you draw the skeletal formula for E/Z isomers? and how do you know how to change what?




First would be (E / Trans) pent-2-ene
Second would ( Z / Cis) Pent-2-ene

way i remember is that Z isomers have a bucket shape, and E is just normal skeletal formula
Original post by bagelbe
I don't understand why people are saying past papers don't prepare you for the exam??? :/



Original post by High VOLTAGE
How do you draw the skeletal formula for E/Z isomers? and how do you know how to change what?



Original post by bagelbe
Yeah, I blame OCR because they always seem to take a bit from the book that is really small part of it and then write a 6 mark question on it &gt;:frown:



Original post by bagelbe
Varies between papers, but I'd say between 75-80%?



Original post by High VOLTAGE
Salaam bro could you help me please

How do you draw the skeletal formula for E/Z isomers? and how do you know how to change what?

Do you have to draw dots on your radicals or not

also, when do you draw these dots

some mark schemes take away marks for drawing dots on radicals, some penalise you for not drawing them

what!
Original post by EternalDoom


First would be (E / Trans) pent-2-ene
Second would ( Z / Cis) Pent-2-ene

way i remember is that Z isomers have a bucket shape, and E is just normal skeletal formula


THANK YOU !
and do you draw the bucket and then just extend however many carbons you need from there?

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