invisibleswords
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Can someone shed some light on how I'd go about answering this?
I'm not asking for the answer, just pointers on how I can work it out for myself.
I get that colour changes come from:
- the identity of the metal ion,
- identity of the ligands
- oxidation state of the metal ion

but have no idea what that actually means with this actual question:

Why would a change in colour be expected in going from the blue Chromium complex to the green Pentaquasulfatochromium III complex?

[Cr(H2O)6]3+↔ [Cr(H2O)5(SO4)]+
Blue >>>>>>>>>Green
coloured >>>>>>Coloured
complex >>>>>>complex
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VioletPhillippo
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(Original post by invisibleswords)
Can someone shed some light on how I'd go about answering this?
I'm not asking for the answer, just pointers on how I can work it out for myself.
I get that colour changes come from:
- the identity of the metal ion,
- identity of the ligands
- oxidation state of the metal ion

but have no idea what that actually means with this actual question:

Why would a change in colour be expected in going from the blue Chromium complex to the green Pentaquasulfatochromium III complex?

[Cr(H2O)6]3+↔ [Cr(H2O)5(SO4)]+
Blue >>>>>>>>>Green
coloured >>>>>>Coloured
complex >>>>>>complex
Hi,

I think they might just want you to identify the things that you've listed above e.g. the identity of the metal ion is the same but the type of the ligands has changed.
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invisibleswords
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(Original post by VioletPhillippo)
Hi,

I think they might just want you to identify the things that you've listed above e.g. the identity of the metal ion is the same but the type of the ligands has changed.
Thanks for your response. What really confuses me is the appearance of SO4 on the right. If it is an equilibrium it should either be on the left or be shown as added.

I'm just stuck on this one question before I can submit my assignment.
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charco
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(Original post by invisibleswords)
Thanks for your response. What really confuses me is the appearance of SO4 on the right. If it is an equilibrium it should either be on the left or be shown as added.

I'm just stuck on this one question before I can submit my assignment.
They are not showing a balnaced equation, merely the bits in which you are interested.

The ligand is changing and, with it, the ligand field splitting energy.

Hence, a different energy value is needed for electron transitions between non-degenerate 'd' orbitals and, as E = hc/lambda, a different wavelength of light is absorbed and the colour observed changes.
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