CU+nacl

[CPL.Luke]

sorry to ask such a simple question, but I've been screwing with plasmas and a microwave, and I got this greyish ash when copper and salt were put into a microwave, some of the ash also had a bronze hew to it, I don't know if that was just a mixture of copper and whatever the ash was, but anyway just wondering if anybody could help me out here

 

 

P.S. the microwave proides enough energy to both make the copper enter a gaseous state and ionize it, so energy is not a problem

[DV8 2XL]

My guess it would be a crude Sodium Bronze.

[CPL.Luke]

sorry for my ignorance of chemistry, but could you give the chemical symbol for that, I have no idea what constitutes a "bronze"

[YT2095]

it`ll be atomised copper deposits, you get the same effect when you weld with copper too, the "Ash" would most likely still be your salt but in a very fine powder.

[DV8 2XL]

Ya. YT's take is the more likely.

 

For reference a bronze is any alloy of copper.

 

Sodium bronze is NaCu although all species in the form: NaXCu, where X is another metal is generaly refered to as a sodium bronze.

[CPL.Luke]

cool thankyou,

 

also I had an odd experience with aluminum foil. First off there was still some copper in the bottle that could have contaminated the aluminum, however when I placed the aluminum foil in the microwave same as the copper and salt, it seemed to cake up into an odd (solid) ash of sorts around the (relativly) normal aluminum foil. this ash crumbled very readily as well when touched.

 

any ideas?

[YT2095]

POSSIBLY sodium aluminate in this instance, with chlorides of both.

[woelen]

Most likely it is Al2O3. If you heat Al-foil in a flame, then you'll also see it shrink and crumble when it becomes sufficiently hot. The very hot Al-metal is oxidized by oxygen from the air to Al2O3.

[YT2095]

woelen, what about the salt though?

 

the copper in there would have had little to no effect sure, but the salt and alu could react, and although there would be O2 in there, the Cl would do a better job at oxidising it, and the sodium would take up with the O2 and moisture to make the sodium aluminate.

 

equaly possible in my opinion.

[DV8 2XL]

I'd have to go with weolen on this one YT, the energies for the path you are proposing aren't as good as the Al2O3 which would probably form before the NaCl dissociated.

[woelen]

the Cl would do a better job at oxidising it

Do you think the Cl can oxidize the Al? The Cl is present as Cl(-) ions (of course you know that ) and will not be transformed to Cl atoms or Cl2 molecules.

 

and the sodium would take up with the O2 and moisture to make the sodium aluminate.

The sodium ions also remain present as ions.

 

The Cl and Na will not be available as elements at the temperatures involved in the microwave.

 

I think that the temperature needs to be thousands of degrees centigrade, before free sodium atoms and chlorine atoms become avaiable.

 

I can imagine formation of an aluminate, but the mechanistic pathway to this certainly will not be through chlorine and sodium in the zero-oxidation state. If sodium aluminate is formed, then the only reasonable pathway could be formation of Al2O3, which in turn reacts with NaCl, forming NaAlO2 and AlCl3. In this pathway, the sodium and chlorine remain at oxidation states +1 and -1 all the time. This reaction may occur at very high temperatures when the NaCl melts, but I do not expect this to happen in the microwave experiment.

[YT2095]

when I considered that Copper metal was atomised and then condensed again in a prior experiment of his, it didn`t seem inconceivable that such a reaction with NaCl and Al metal in the presence of O2 could occur, I agree that Al2O3 would indeed be created and the possibility of AlCl3, NaAlO2, free Chlorine gas, unreacted Al and NaCl should also be present.

 

a "disorganised" reaction such as this could lead to a whole host of different products in differing quantities each time you try it, there`s too many alterable factors involved, it`s a bit "messy" to give a 100% definative answer to without actualy being there to test afterwards.

 

not only that but I`m fairly certain that if ran long enough AlCl3 could also break down again as it`s alot more ionic than the Oxide (which shouldn`t react as much to the MW energy)

[CPL.Luke]

"This reaction may occur at very high temperatures when the NaCl melts, but I do not expect this to happen in the microwave experiment."

 

there was what appeared to be melted salt on some of the glass, and the copper wire.

 

 

first let me say that none of these observations are scientific and were just me playing around, I am going to conduct scientific observations when I get a microwave that can easily be sacrificed (sometime in september hopefully)

 

 

I hadn't thought about the salt contamination (there was a very extreme presence of it) and quite possibly copper as well (the copper melted its way into the glass, although it was exposed)

 

The temperatures involved in this experiment are equivalent to those of an arc welder. this is accomplished because in the absense of food in a microwave to absorb the energy, the microwaves build up until electrical sparking and the like occurs. the plasma wich appeared in the bottle was most likely a mix of copper and air, in later experiments copper and Na, Cl (possibly only one of them, as I am unaware at what temperature these vaporize and subsequently ionize)

 

I am fairly certain that the temperature was sufficient to vaporize the aluminum as a silvery metal appeared to coat some of the copper beads that were imbeded in the glass near where the bulk of the plasma leveled off and floated.

 

also be aware that there is alot (and I mean alot, on several occasions spurts of ball(?) lightning erupted and circled the glass several times(rolling alongthe wire present as well) until coming to rest) of electrical sparking involved here so that should have aided in breaking the bonds between the sodium and chlorine. The entire microwave reeked of ozone after the experiment, after the sodium experiment ran it also took on the very strong oder of salt, so at least some of it must have been dispersed into the air.

 

 

Edit: I just checked on wikipedia and the boiling point of copper is higher than that of aluminum at 2562 degrees C. and I personally observed the vaporization of copper in the microwave in both watching the copper burst into "flame", observing divets in the glass where the copper had become hot enough to melt a small divet into the glass, however the copper then grew hot enough to burn (using burn because that is far closer to the effect that I witnessed than a boiling, the instences where the copper vaporized appeared to skip the melting phase) leaving an empty divet in the glass. I also noticed small condensed beads of copper at the top of the bottle (where the plasma was located) that show that it had vaporized and condensed. Finally in other instences where the copper was on a flat dish I noticed thin even scattering of what could only have been copper on some sections of glass

[YT2095]

you can easily attain temps in the order of several thousand degrees in a MW by the action of Arc ablation and or the presence of plasma(s). more than plenty to melt NaCl and parts of your glass even, be VERY carefull, and check your microwave seal regularly too, a badly leaking MW isn`t funny, it can harm you and/or other electrical equipment local to it.

[CPL.Luke]

yeah I melted glass several times in the microwave although for some reason (still thinking of why) it rarely happens except when a piece of metal is directly resting on it, when plasma is just held inside of the bottle the glass doesn't melt (the uneven heating will shatter it, but it won't melt) there was a sizeable amount of steel in this region once and it was flowing down to the bottom of the bottle (wether this was because of the microwaves or heat, or both I'm not sure)

 

anyway how do you check for leaks in the microwave? I now I havn't felt any heat while in proximity to the microwave (tis a good sign I would expect) and it is very new so it shouldn't be leaking that badly

[YT2095]

you could probably pick one up for a few dollars at Radio Shack or similar