Edexcel Chemistry Unit 5 June 19 2012

Phenylamine with Cu2+ ions:




so:


[Cu(H2O)6]2+ + 2Phenylamine --->>> [Cu(Phenylamine)2(H20)4]2+ + 2H2O

as a Ligand .... dative covalent bond from the lone pair of electrons on the nitrogen...

Thanks . Can I just ask what do we need to know about the chemistry of chromium and copper ?

Phenylamine with Cu2+ ions:

When drawing 3D complexes, do we hav to show the lone pair on the ligand, like on the O on H2O or CL

Sorry for the late reply but in my chemistry text book, (Edexcel Chem by Graham Hill and Andrew Hunt), has;

*chloro ligands Cl-
*fluoro ligands F-
*cyano ligands CN-
*hydroxo ligands OH-

Ligands cause the metal ion's D orbitals to be split into two energy levels. A higher and lower level. Wavelengths of light with energy the same as that of the difference between energy levels are absorbed and the energy is used to promote electrons from the lower energy level to the higher level (This is a d-d transition). The electrons shortly 'fall back' to the lower level, releasing the energy difference as heat(not light). Hence, the solution appears the complimentary colour to that of the wavelength absorbed.

However, if the D orbitals are full, then promotion cannot take place, and so no light is absorbed -> it appears white. Equally if there are no ligands, there is no splitting of the d orbitals and hence, no absorption can take place.

I'm just doing the June 2010 past paper atm, and I don't understand how to work out the electrode potential for the last question of section B. Can anyone talk me through it please because I'm really struggling with it and don't know where to start.

What unit is this for?

anyone know what the past raw marks have been like to get an a or an a*?

Its one of the phenylamine reactions - unit 5

I take it you don't do AQA chemistry?

Do we have to know about the procedure for thin-layer chromatography?

Do we have to know about the procedure for thin-layer chromatography?

Haha we are all doing June 2010 today
I struggled with this too! But think i got it - think its one of those 'looks harder than it is' ones!

So it's saying: V4 is going to V5, and V4 is going to V3 ... will this happen?

so first
V4 >>> V3 (which we did in b(i))
E value = +0.34
This is reduction


then V4 >>> V5 (given in (iii))
E value = +1.00
This is oxidation


Using E cell = E of chemical being reduced - E of chem being oxidised:

E cell = +0.34 - +1.00 = -0.66 V

As the E value is -ve this reaction won't be feasible under standard conditions

Hope that helped

It is in the spec. Why don't you read through the spec? It may seem useless, but I believe you may actually find it beneficial. I personally flick through it to know what I actually need to learn as I use Facer as well.

Nitrobenzene forms a layer which floats on top of the acid, how would we separate the nitrobenzene?

Washing to remove acid?
Separating funnel?

I just read through spec and I can't find the reaction between amino acid and ninhydrin in George Facer D:

Separating funnel seems to make sense here.