Sciencemadness Discussion Board - Copper compound on aluminum foil??

Copper compound on aluminum foil??

bigtrevs98 - 10-5-2015 at 20:49

So I was making copper(ii) acetate (again) and I got what I think to be like copper oxide sludge but I doubt it (and if I'm wrong please correct me) building up on the sides of the copper while the solution evaporates. (1:1 3% h2o2/5% acetic acid.
Well some of the "copper oxide" got on some aluminum foil I had laying around in. The light blue-green sludge automatically got little grey specks in it.
So I decided to try to recreate it and see if anything new would happen. I took BB size ball of the sludge and put it on a piece of foil and folded the foil onto the sludge. It began to get hot and even smoked a little. I open it up and it looked like it kinda burnt it... uhh what happened?

Edit: after the sludge Burns up it turns red/brown

[Edited on 11-5-2015 by bigtrevs98]

Mesa - 10-5-2015 at 21:11

You may want to study the "reactivity series" a bit...

blogfast25 - 11-5-2015 at 05:08

3 Cu<sup>2+</sup>(aq) + 2 Al(s) === > 3 Cu(s) + 2 Al<sup>3+</sup>(aq)

Quite exothermic. Don't mix copper solutions with Al metal.

Milan - 11-5-2015 at 05:10

Quote: Originally posted by bigtrevs98

So I was making copper(ii) acetate (again) and I got what I think to be like copper oxide sludge but I doubt it (and if I'm wrong please correct me) building up on the sides of the copper while the solution evaporates. (1:1 3% h2o2/5% acetic acid.
Well some of the "copper oxide" got on some aluminum foil I had laying around in. The light blue-green sludge automatically got little grey specks in it.
So I decided to try to recreate it and see if anything new would happen. I took BB size ball of the sludge and put it on a piece of foil and folded the foil onto the sludge. It began to get hot and even smoked a little. I open it up and it looked like it kinda burnt it... uhh what happened?

Edit: after the sludge Burns up it turns red/brown

[Edited on 11-5-2015 by bigtrevs98]

In the sludge you have copper and acetate ions, copper was displaced out of the solution by aluminium ions, because aluminium is more reactive than copper, the red/brown color is powdered copper metal. Again as Mesa said study the reactivity series a bit. Wikipedia's the best place to start so here a link: http://en.wikipedia.org/wiki/Reactivity_series

Edit: Look like blogfast beat me to it while I was typing

[Edited on 11-5-2015 by Milan]

bigtrevs98 - 11-5-2015 at 15:37

That you both for the link I kinda skimmed it a bit (a bit busy will read asap tho) but one of my "kinda" questions weren't answered . Was it copper oxide that was built up on the copper (at start it was clean copper)or something else?

Edit: so why is the light blue stuff taking over my copper acetate???

[Edited on 11-5-2015 by bigtrevs98]

Texium - 11-5-2015 at 15:42

No, CuO is black. If it's blue-green or bluish white, it's likely copper acetate or copper oxy-acetate, respectively. The second picture looks somewhat like copper oxy-acetate but it's really hard to tell because of the low quality. It's formed partially when you dissolve copper in a mix of acetic acid and hydrogen peroxide, or in larger amounts with more concentrated peracetic acid.