Qualification > Sciences
ALL CIE CHEMISTRY DOUBTS HERE !!
ahmedigcse4eva:
Hey guys,
Would you please tell me what are the topics in AS chem cambridge, and if there notes for the AS chem.
Thanks alot
Most UniQue™:
--- Quote from: ahmedigcse4eva on September 14, 2011, 08:20:56 pm ---Hey guys,
Would you please tell me what are the topics in AS chem cambridge, and if there notes for the AS chem.
Thanks alot
--- End quote ---
Here's the syllabus, read it and you'll know what are included:
http://www.cie.org.uk/qualifications/academic/uppersec/alevel/subject?assdef_id=736
And notes, you can find it here:
Notes Here
Notes Here
GOOD LUCK Mate!
ahmedigcse4eva:
many thaaaaaaaanks ;D ;D ;D
MKL:
Hi all, I'm real puzzled by this question from the M/J 2011 paper. Question 29 Paper 12 asks for the change in number of chiral carbons of cholesterol under 1) cold dilute acidified manganate and 2) hot concentrated acidified manganate. I'm pretty sure the answer is +1 and -1 but the mark scheme says it is +2 and -1. Can anyone give me a hand on this?
Becca:
Hi, @MKL...
It's +2 because the cold dilute acidified KMnO4 produces a diol by adding a hydroxyl group to each of the two carbon atoms in the carbon-carbon double bond within the molecule. This creates two chiral carbon atoms for those two carbon atoms... On the ather hand, when hot concentrated acidified KMnO4 is used, one chiral caron atom is lost because the hydroxyl group within the original cholesterol molecule is oxidised to form a ketone functional group, so the carbon atom attached to that hydroxyl group ceases to be a chiral carbon atom.
Hope you understand my explanation! :)
Becca
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