MgSO4+copper=(hopefully) copper sulfate

[Oban Kobi]

Ok, so I read other posts on using epsom salt as an electrolyte, and copper electrodes with 9v to create copper sulfate. This method apparently worked for some people, but my water isn't blue, it's yellow. I tried to think of anything that's yellow, and came to sulfur. It's a really fine yellow powder suspended in the solution, and I'm not sure what it is. I'd sniff it, but that doesn't seem very wise. Any ideas? Thanks:-)

 

I just touched it, to see if any temperature change had occurred, and it feel slightly warm, compared to the copper/water mixture I have sitting next to it in an identical container.

[DrDNA]

Exactly what did you do? In detail.

[Oban Kobi]

Sorry bout that, was in a bit of a hurry. Anyway, I mixed MgSO4 with water (I don't know how much), and hooked up two copper (pre1985) pennies to the terminals of a nine volt battery. I then placed the two pennies into the water and waited. A while later, the water was yellow. It should have been blue, copper bonding with the sulfur and leaving magnesium as a precipitate. Instead, a fine yellow powder appeared in the water. It has now concentrated itself in a pinwheel pattern, a hub at the middle, and spindly arms swirling of, so it's obviously not homogeneous. I was just wondering if the yellow powder was sulfur, and if not, what it is. I did get it to work though, using clean copper wire instead of a corroded 90 something percent copper penny. Pretty cool stuff.

[Darkblade48]

IIRC, the electrolysis of copper terminals in a MgSO4 solution will not create copper sulfate, but copper (II) hydroxide, Cu(OH)2. This is the light blue precipitate that you observe in the water when you use a clean copper wire instead of a penny.

 

You'd have to look up the percent composition of the pre 1985 pennies to determine exactly what the yellow precipitate was; however, I find it unlikely to be sulfur.

 

Also, copper does not spontaneously bond with the sulfate, leaving magnesium as a precipitate.

[Oban Kobi]

Ok. I'm kind of new at this, so could you explain why it is copper hydroxide, not sulfate? What causes that to happen?

 

Will do, thanks.

 

I don't know how to respond to that, cause I'm a bit of a newbie, but isn't copper sulfate CuSO4? That would leave hydrogen to form and be released as a gas, and the magnesium to just drop away. For copper hydroxide, Cu(OH)2, the MgSO4 would be left intact, and no gas would be released, since it would be bonding with the copper. I'm not sure if that's right, so correct me if I'm wrong, but that's how I thought of it.

[John Cuthber]

Copper (I) oxide can be yellow if it's finely divided.

[Darkblade48]

Well, if copper was forming copper sulfate, and leaving magnesium as a precipitate, the magnesium should react with the water, forming insoluble magnesium hydroxide (a white precipitate) instead.

 

Thus, if you had copper sulfate with magnesium hydroxide, you should have a blue solution with a white precipitate at the bottom (after you let it settle, of course).

 

However, in my experience, the I tend to get a dirty, light blue precipitate, which then disappears upon upon addition of sulfuric acid. The solution also becomes a slightly darker shade of blue.

[Oban Kobi]

Copper (I) oxide can be yellow if it's finely divided.

 

Thanks

 

 

Well, if copper was forming copper sulfate, and leaving magnesium as a precipitate, the magnesium should react with the water, forming insoluble magnesium hydroxide (a white precipitate) instead.

 

I did get a white material that was a bit like calcium, crumbling easily, and insoluble. It appeared rather quickly on the copper attached to the cathode. Could that be magnesium hydroxide?

 

The solution is blue, though for some reason, some of it settled as a blue precipitate in small pieces. As for a white one, it's difficult to tell, but it appears as though there is a bit of white in a few places, in little flake-like things.

 

Not quite sure what you're saying here. I know what sulfuric acid is, I just haven't ever used it. Why does it do that?

[Darkblade48]

The solution may appear blue due to the fine precipitate (it stays in suspension quite easily). However, if you let it settle for a while (perhaps a day or two), you should see that there is a blue precipitate, and that the solution is not homogenous.

 

In my experience with this kind of electrolysis, the product I get is Cu(OH)2. Since it is a hydroxide, reaction with sulfuric acid will generate copper sulfate (as well as water).

 

Hope that helps

[Oban Kobi]

You're right, I looked at it today, and all of it has gathered at the bottom

 

Now if only I could get my parents to let me get sulfuric acid. Hmmm....

 

Thanks Darkblade, it does.

[jaaz95]

ya so i did the same thing and i got a large crystal structure as well as a large amount of a blue persipitate and the copper electrodes had a redbrown layer on them. i wikipediad this and it said that it does infact make copper sulfate and magnesium hydroxide. so i dunno cause i've made this a few times now and im using distilled water and everything and it always come out the same. so darkblade either im not doing something right or your wrong

[Oban Kobi]

Woah, way to resurrect a 3 year old thread...

But yeah, I've had 3 years to think about it

Got a 5 on my AP test Thanks in part to the threads on the site.

But really, I think this needs to be closed...

 

PS: Darkblades right as far as I can remember

[Charlatan]

Ok, so I read other posts on using epsom salt as an electrolyte, and copper electrodes with 9v to create copper sulfate. This method apparently worked for some people, but my water isn't blue, it's yellow. I tried to think of anything that's yellow, and came to sulfur. It's a really fine yellow powder suspended in the solution, and I'm not sure what it is. I'd sniff it, but that doesn't seem very wise. Any ideas? Thanks:-)

 

I just touched it, to see if any temperature change had occurred, and it feel slightly warm, compared to the copper/water mixture I have sitting next to it in an identical container.

 

{Making copper sulfate with the blood of the saints! Oh yes!]

 

Well, riddle me this then; what would happen if there was salt mixed with metal? You would make a organic and a metal 'mixture'. Salt relays energy and fluids and will settle on the dense metal, but, will not penetrate it unles the salt is boiled or melted, but, that would be the surface or outer layers of the salt that bond with the metal, affecting only the outer layer of the metal.

 

If you do this I will give you a thousand dollars! Unless you do do it, then I will say something else about riddles and concubines and that sort of thing!

[John Cuthber]

That's not a riddle it's just gibberish.

[Solinta]

Ok. Hi guys, I read this and then just had to register to reply .

I just did this reaction today, running a 9v battery through two strips of pure copper and through a MgSO4 solution. Hydrogen was produced and A white precipitate formed at the bottom, solution turned a pale blue but that colour is gradually darkening. I would say it is - MgSO4 + H20 + Cu = MgOH + CuSO4 + H2