Effects of concentration on the colour of a solution?

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Offline champagneflowers

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I did a lab and we had to test the colour of solutions with different amounts of water and kool aid. Can you answer any of these?

Is the nature of the solute important when preparing a solution of a specified concentration?
What happens to the concentration of a solution if more solute is added to the same volume of solvent?
What happens to the concentration of a solution if more solvent is added to the same amount of solute?

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Offline RD

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Re: Effects of concentration on the colour of a solution?
« Reply #1 on: 30/01/2014 04:28:22 »
Sounds like homework.  We're not supposed to answer homework questions, so best I can do is a wikipedia link ... http://en.wikipedia.org/wiki/Colorimetry_%28chemical_method%29
« Last Edit: 30/01/2014 04:30:34 by RD »

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Offline SorryDnoodle

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Re: Effects of concentration on the colour of a solution?
« Reply #2 on: 30/01/2014 04:37:23 »
If you have a spectrophotometer you can make a series of solutions of x molar and build a model of how it changes.


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Offline lightarrow

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Re: Effects of concentration on the colour of a solution?
« Reply #3 on: 30/01/2014 11:21:52 »
Remember to compute the equilibrium if in presence of coloured complexes. Example: Fe3+ and SCN- gives red-coloured complexes. If you dilute the solution, those complexes also dissociate, so their concentration, and the resultant colour, is less than what expected from a simple dilution.

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