Didnt have time to revise due to s1 i suggest doin the past papers and look over a2 as some of ur a2 stuff might be in as for another spec if u get what im sayin.
Most of it was difficult but i can see it being done by the really 'smart people', i couldnt do some questions and i havent seen or done past papers so cant compare difficulty
Didnt have time to revise due to s1 i suggest doin the past papers and look over a2 as some of ur a2 stuff might be in as for another spec if u get what im sayin.
Given that spectroscopy shows all the hydrogen atoms in H3AsO3 to be in the sameenvironment, suggest a structure for the acid. What is the geometry around thearsenic atom?
Given that spectroscopy shows all the hydrogen atoms in H3AsO3 to be in the sameenvironment, suggest a structure for the acid. What is the geometry around thearsenic atom?
I don't recognize "NMR" but we've done mass spect like m/z peaks etc and infrared spectroscopy, is it anything to do with these?
Okay scratch that then. Groups/atoms in a molecule are said to be "chemically equivalent" or "in the same environment" if the structure of the molecule is such that they are joined to the same groups/atoms.
e.g.
The molecule is symmetric about the 3rd carbon, so the protons on the 1st & 5th and 2nd & 4th are equivalent.
However the molecule need not be symmetric:
This molecule has almost no symmetry but there are equivalent proton environments on the phenyl substituent (the 6-memebered ring with alternating double bonds), as the 2/6 and 3/5 protons are equivalent (counting clockwise around the ring, starting where the phenyl is joined to the other part of the molecule).
NMR is similar, mainly an A2 thing. Chemical equivalence is when the atom is joined to the same atoms within a molecule (so if you could draw a line of symmetry down a molecule, atoms either side of that line will be eqivalent
There doesn't necessarily need to be symmetry: see above.