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Author Topic: Why does my copper wire dissolve during electrolysis in salt water?  (Read 8404 times)

Offline SorryDnoodle

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Hi!

Since this is my first post here I would like to introduce myself, The names Daniel and I've got a bit of an interest in chemistry and I am in the process of making some thermite.

I have begun creating rust through putting an old mobile charger at 4.5 volt in salt water with Iron connected to the positive wire and leaving the negative wire in the water.

But the negative wire seems to dissolve into the water, I was unaware of this and I have no idea what is created through this process, is it in anyway harmful and how can I stop it?

I find it hard to create a good quantity of rust of my wire keeps dissolving into the water stopping the electricity.

Thank you!
« Last Edit: 17/07/2012 23:22:50 by chris »


 

Offline imatfaal

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Re: Dissolving Copper wire by accident in salt water
« Reply #1 on: 17/07/2012 16:50:24 »
Bits of old abandoned car?

Seriously thermite is seriously dangerous stuff - it gets very hot and probably not the best stuff to start on for practical chemistry.  Too much moisture, wrong proportions, or trapped impurities can cause nasty bangs - and they liberate molten iron droplets.
 

Offline SorryDnoodle

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Re: Dissolving Copper wire by accident in salt water
« Reply #2 on: 17/07/2012 19:02:33 »
I know it is dangerous, as with most things in life, but I am a cautious person, i'll be using a slow burning fuse connected to some Magnesium to ignite it, now my if you know the answer to my question please help, It's not really about the thermite itself more about the process of making it.
 

Offline Bored chemist

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Re: Dissolving Copper wire by accident in salt water
« Reply #3 on: 17/07/2012 21:34:01 »
Are you sure you know which is + and which is -?
 

Offline SorryDnoodle

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Re: Dissolving Copper wire by accident in salt water
« Reply #4 on: 17/07/2012 22:33:45 »
Yes, I put the two wires in alone at first to see which one got the bubbles on it, then I connected my Iron to the one that got the bubbles, and left the other wire alone in the water.

And then it started to disolve.

What exactly is created when the copper disolves itself into the water?
 

Offline Bored chemist

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OK, so, since both wires should bubble you don't know which is + and which is -.
 

Offline SorryDnoodle

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Ok.. My honest mistake, I believed only the positive wire should get the bubbles..

I will retry the expirment when I get home and I thank you for the answer to that question.

But I was just wondering, what Solution is created when the Copper wire is disolved?
 

Offline Bored chemist

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Probably copper (II) chloride as much as anything else.
 

Offline SorryDnoodle

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So the copper absorbs Chloride from the salt, what happens to the Sodium?

Sorry If I am asking a lot of questions but it's very interesting :D
 

Offline SorryDnoodle

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I have redone the experiment...

Used an old car battery so I was sure which was positive and negative, the negative wire seems to release a whiteish green liquid along with what I assume is Hydrogen from the water fairly rapidly, I would assume it is copper (II) chloride as it is also making the water green and also sets to the bottom pretty quickly.

But the good news is the Iron I added is rusting away like I hoped it would, but I am unsure how to extract the rust from the water when it's contaminated with the copper, should I use another metal for conductivity perhaps?

Any suggestions which would be suitable in this case?

I am using a 12 Volt car battery, don't dare use it for long periods of time due to the creation of hydrogen and I am not working in a well ventilated area at the moment, planning on setting up an outside area of work but for the moment I am stuck in a garage.
« Last Edit: 20/07/2012 21:16:31 by SorryDnoodle »
 

Offline evan_au

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It's not very efficient to spend energy producing iron oxide when the natural tendency is to turn iron metal into iron oxide by simple exposure to the atmosphere. A lot of energy was originally spent turning the iron ore (often iron oxide) into iron metal.

But seriously, thermite is dangerous.
If you want to make a small bang, try lighting a few milliliters of the hydrogen you have produced - with the right precautions: wear goggles & heavy gloves, and leave the end of the collection vessel open.
 

Offline SorryDnoodle

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Thermite does not even create a bang, it melts into a pile of iron, Thermite is also very hard to ignite, a regular spart or lighter would't ignite it, exposing it to the sun would only help make it more stable removing moisture from it.

Themite is very easy to control, and I will do a small test of my batch before I use all of it in a wide open field with a fuse to ignite it, when I am at a good distance away.

Hydrogen explodes however, and is easily ignited, and is a gas and it is toxic.

I'm going with the stable, hard to ignite, not exploding Thermite first thank you, I had hoped this forum wasn't full of people saying that something is dangerous, life is about risks and what I am doing isn't even close to any risk, I have access to 98% Sulfuric acid, 98 % Hydrochloric acid, Potassium Cyanide, and several other strong acids.

If I wanted to play with the most dangerous thing I can find I would be doing that, But I am going slow and starting out with thermite, a stable hard to ignite NOT exploding substance, now either help or please, leave.

ps. If you want large quantities of Rust and you don't own a scrapyard, yes it is very effective unless you want to wait a long while and scrape it all of by hand by letting nature do it's own work...
« Last Edit: 21/07/2012 17:21:14 by SorryDnoodle »
 

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