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Aqa chem 4/ chem 5 june 2016 thread

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Do we need to know about bond angles in benzene compared to the cyclo's
Original post by Hadigy
Do we need to know about bond angles in benzene compared to the cyclo's


Yes, bond angle in benzene is 120 compared to the cyclo which is 109.5
Original post by thehollowcrown
Sn/HCl used for reducing nitrobenzene to aromatic amines
LiAlH4 used for reducing nitriles to amines
NaBH4 is only strong enough to reduce ketones and aldehydes to alcohols


can i use H2/Ni for reducing nitriles?
And thanks for the reply
Reply 543
Original post by confusedkid1997
can i use H2/Ni for reducing nitriles?
And thanks for the reply


i belive you can
Original post by Hadigy
Do we need to know about bond angles in benzene compared to the cyclo's


Not for CHEM 4 we don't, we do need to know about bond strength and stability in benzene though and be able to compare it to cyclo. i.e explain why it is more stable.

Good Luck
Original post by confusedkid1997
can i use H2/Ni for reducing nitriles?
And thanks for the reply


Yeah, pretty sure it always has that in the mark scheme as well as LiAlH4
Original post by Jackpalmer1996
Not for CHEM 4 we don't, we do need to know about bond strength and stability in benzene though and be able to compare it to cyclo. i.e explain why it is more stable.

Good Luck


they have asked a question comparing bond angles before
Reply 547
Original post by Jackpalmer1996
Not for CHEM 4 we don't, we do need to know about bond strength and stability in benzene though and be able to compare it to cyclo. i.e explain why it is more stable.

Good Luck


you do, it came up a few years ago
Original post by Kaya22
i belive you can


If they ask for conditions they are high temp. and pressure as well.
Original post by Kaya22
i belive you can

thanks man , good luck :smile:
Do we need to memorise the pH indicators and their pH ranges?
(edited 7 years ago)
Reply 551
Original post by vaishnagaraj
Do we need to memorise the pH indicators and their Ph ranges?


nope :smile:
Original post by vaishnagaraj
Do we need to memorise the pH indicators and their Ph ranges?


you just need to know phenolphthalein and methyl orange
Original post by Kaya22
nope :smile:


Thank you!
Original post by vaishnagaraj
Do we need to memorise the pH indicators and their Ph ranges?


The only one we need to memorise is phenolphthalein which is 8.3-10 and colourless at low pH and pink/red at high pH (they allow pink or red in all mark schemes from past papers.
Good Luck
How would you name a compound which shows e/z isomerism, having 2 methyl groups on one side and one bromine group on the other side with one h atom? Do you have to consider priority or something?
(edited 7 years ago)
Original post by Hadigy
How would you name a compound which shows e/z isomerism, having 2 methyl groups on one side and one bromine group on the side with one h atom? Do you have to consider priority or something?


Alphabetical order so bromo comes first
Original post by thehollowcrown
Alphabetical order so bromo comes first


Thanks. So would it be Z or E isomerism?
Original post by Hadigy
Thanks. So would it be Z or E isomerism?


actually the compound you have described doesn't have the same functional group attached to either carbon so it can't be E/Z isomerism
Original post by Anon_98
Hey guys, just wanted to say that if anyone wanted a quick summary on everything you need to know for the course as a bit of last minute revision stuff then I made a thread. Don't know if it'll be useful but here:

http://www.thestudentroom.co.uk/showthread.php?t=4159211

Anyway good luck, hope it goes well for you all. :woo:


You are so great!

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