Sciencemadness Discussion Board - Question about my filtrand- CaSO4?

Question about my filtrand- CaSO4?

NiK - 26-11-2013 at 09:17

So I was making some Copper (II) Chloride to react with Al foil and I used a method of adding NaCl to CuSO₄(aq) to get a "soup" of ions; these ions would be Na⁺, Cl^-, Cu⁺², SO₄^-2, right?

From there I added CaCl which would disassociate into Ca⁺ and Cl^-. Then the only insoluble thing that would form would be Ca₂SO₄?

This is what I filtered off of my CuCl₂ solution (which still has Na⁺ ions in it??). The greenish color started to show once it was a little drier, before that it was only a light blue color. Is this product Calcium Sulfate that I just didn't filter well enough so it has color from the Cu⁺² or Na⁺ ions?

Also, not part of the title but would be considered "Beginnings" as well. I reacted some Al foil with some NaOH(aq) to capture the hydrogen gas in a balloon. I got a slimy thick black liquid as my left over...it's not completely a solution because the black will sink to the bottom leaving a clear layer of slimy liquid on top. After pouring some of it into a watch glass and letting it sit, the black dried as a veryyy thin layer on top of the liquid, but I'm guessing there is more black stuff inside the solution? What do you guys think this is? I posted a topic about capturing the H₂ gas and talked a little about this; someone suggested it might be Si that gets added to Al foil?? I'll post the pic as a reply, as far as I can tell I can only add one pic per post.

It says I can't post that often...2 posts at once? Watch out mad spammer here...I'll give it a minute and see if I can post again with the picture in a reply .

[Edited on 11-26-13 by NiK]

[<a href="u2u.php?action=send&username=bfesser">bfesser</a>: attached second image]

[Edited on 26.11.13 by bfesser]

bfesser - 26-11-2013 at 09:23

A better route:
   CuSO4(aq) + Na2CO3(aq) → [CuCO3](s) + Na2SO4(aq)
   [CuCO3](s) + 2HCl(aq) → CuCl2(aq) + H2O(l) + CO2(g)

Please keep the topics <a href="viewthread.php?tid=27447#pid308546">separate</a>. If you feel that your questions weren't sufficiently answered you'll need to provide more data for us to go on (specific gravity, mpt, etc.).

[Edited on 26.11.13 by bfesser]

MrHomeScientist - 26-11-2013 at 09:26

You could have skipped the NaCl - that just adds unnecessary sodium atoms. You're right in that the calcium would precipitate, and leave you with a copper chloride solution:
CaCl₂ + CuSO₄ --> CaSO₄(s) + CuCl₂

If you combine things stoichiometrically, this should yield quite pure copper chloride! When you isolate some, try dehydrating it in a propane torch flame (carefully) - the anhydrous form is brown!

Edit: bfesser posted while I was writing this. That is also a great method of preparation, and one I've done many times before.

Not sure why you wouldn't be able to post. I didn't think we had any restrictions here. And you can add more than one picture per post - notice the "Multi-Attach" directly below the attachment box.

[Edited on 11-26-2013 by MrHomeScientist]

NiK - 26-11-2013 at 09:28

Quote: Originally posted by bfesser

A better route:
   CuSO4(aq) + Na2CO3(aq) → [CuCO3](s) + Na2SO4(aq)
   [CuCO3(s) + 2HCl(aq) → CuCl2(aq) + H2O(l) + CO2(g)

I actually did that too! I was trying multiple methods, I used NaHCO₃ instead. But then I reacted it with HCl to get CuCl₂

MrHomeScientist - 26-11-2013 at 09:35

Quote: Originally posted by bfesser

A better route:
   CuSO4(aq) + Na2CO3(aq) → [CuCO3](s) + Na2SO4(aq)

Now that I think about it, doesn't this produce basic copper carbonate instead? Via:
2 CuSO₄ + 2 Na₂CO₃ + H₂O → Cu₂(OH)₂CO₃ + 2 Na₂SO₄ + CO₂

If your ultimate goal is CuCl₂ it doesn't really make much difference, though it would affect stoichiometry.

bfesser - 26-11-2013 at 09:37

Hence, the square brackets. I didn't want to confuse him with the complexities of copper coordination chemistry and all that.

shaheerniazi - 26-11-2013 at 09:58

Another route is to simply react copper with hydrochloric acid.

Cu+HCL+H2O2->CuCl2+H2O

I have edited thanks, anyway since copper is quite unreative so we first oxidise it with hydrogen Peroxide.

[Edited on 27-11-2013 by shaheerniazi]

MrHomeScientist - 26-11-2013 at 10:15

Copper does not react with hydrochloric acid. Double check your equation - where does the oxygen come from? Nitric acid is about the only common acid that dissolves copper. It's been mentioned around here that you can use a combination of HCl and H₂O₂ to attack copper metal, but I have not tried this myself.

[Edited on 11-26-2013 by MrHomeScientist]

blargish - 26-11-2013 at 10:16

Quote: Originally posted by shaheerniazi

Another route is to simply react copper with hydrochloric acid.

Cu+HCL->CuCl2+H2O

That reaction will not occur. The HCl is not a strong enough oxidizer to oxidize the Cu to Cu²⁺. You need a good oxidizer in the reaction. Hydrogen peroxide should work:

Cu(s) + H2O2(aq) + 2HCl(aq) --> CuCl2(aq) + 2H2O(l)

Some O₂ gas will be evolved as well, as the copper will increase the decomposition rate of the peroxide.

UnintentionalChaos - 26-11-2013 at 10:18

Quote: Originally posted by NiK

So I was making some Copper (II) Chloride to react with Al foil

To what end? For making copper powder in aqueous solution or do you mean anhydrous CuCl2 reacting with aluminum?

If the former, simply adding some HCl or NaCl to CuSO4 solution will catalyze the reaction with aluminum. My preferred method of prepping copper powder is to use granular zinc with a bit of sulfuric acid to reduce copper sulfate. Heating with additional H2SO4 until bubbling ceases will remove residual zinc.

BlackDragon2712 - 26-11-2013 at 12:15

This one is very easy, only ion exchange and chemicals are available in any hardware store. Is the one I use when I need CuCl₂, way better than messing around with HCl, IMO

3CuSO₄ + 2FeCl₃ -> 3CuCl₂ + Fe₂(SO₄)₃(S)

Random - 26-11-2013 at 12:22

It is CaSO4 and Cu2+.