wackyvorlon
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Posts: 18
Registered: 31-5-2006
Location: Sarnia, Ontario, Canada
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Mood: Puzzled
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Prussian blue
I'm still just starting to work with chemistry, and am very much a beginner. So this may be a silly question. I also don't have hard numbers for the
amounts involved, for which I apologize. I'm still getting my equipment together, and at this point it is severely lacking. I did this using an
experiment from the Thames and Kosmos C1000 kit.
I prepared a solution of potassium hexacyanoferrate, and a solution of ammonium iron sulfate. I poured 50ml of distilled water into a measuring cup,
and added ten drops of each solution. This resulted in a very pale blue colouration. I proceeded to add another ten drops of each, and it became
much darker. I noticed that when I added more ammonium iron sulfate that colour would become darker, but adding potassium hexacyanoferrate did not.
I determined this by adding ten drops of the ammonium iron sulfate solution, noted the change. Ten drops of potassium hexacyanoferrate of solution
did not result in a colour change. Then I added ten drops of ammonium iron sulfate solution, noted a colour change. An additional ten drops of
ammonium iron sulfate solution resulted in further colour change.
This could be a case of my simply not doing enough experimentation, but it appears that the colour change is more strongly influenced by the ammonium
iron sulfate solution. Any thoughts are greatly appreciated.
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pantone159
National Hazard
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Posts: 589
Registered: 27-6-2006
Location: Austin, TX, USA
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Mood: desperate for shade
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It depends on the concentration of your solutions!
There is one ferric ion to go with each ferrocyanide (or ferrous and ferricyanide, I couldn't tell which you meant). The particle size of the
precipitate, and hence the physical qualities of the prussian blue, depend on a lot of things.
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