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Zinc
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Wierd...
Our chemistry teacher gave me and my friend some potassium chlorate (one of many chemicals she gave us) and we mixed it with magnesium powder. We
tried to light it with a butane torch bud it didn't ignite . The potassium chlorate
is 20-30 years old but the bottle was never opened before.
The same goes for KBrO3. I mixed it with sulfur (I know it is dangerous to do that) and tried to light it but it didn't ignite. The potassium bromate was also 20-30 years old and never opened before. I am sure that
nothing was wrong with the magnesium and sulfur. Do you know why the mixtures didn't burn? I know that we mixed them good. The powders were as coarse
as flour. Do the KCLO3 and KBrO3 have a limited shelf live?
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Bert
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If your Mg was as old as your oxidizers, it has probably completely oxidized in storage unless it was sealed in an inert atmosphere. Or your
chemicals are perhaps mislabeled.
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12AX7
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FYI, I've never had good luck igniting loose KClO3 and MgAl powder I made myself. Explodes just fine with charcoal and confinement, go figure.
Tim
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Zinc
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| Quote: | Originally posted by Bert
If your Mg was as old as your oxidizers, it has probably completely oxidized in storage |
The Mg is a few months old and was dark grey so it wasn't completely oxidised. If it was completely oxidised it would be white because MgO is white.
3 minutes ago I tried igniting the KCLO3/C mix. It burned but very slow and only a part of the pile burned away. The rest of the pile remained. I also
mixed the KCLO3 with sulfur and it burned good (I know that chlorates and sulfur should not be mixed)
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DeAdFX
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| Quote: | Originally posted by 12AX7
FYI, I've never had good luck igniting loose KClO3 and MgAl powder I made myself. Explodes just fine with charcoal and confinement, go figure.
Tim |
I find Mg strips + powdered Al/KClO3 easy to ignite but Al/KClO3 impossible...
Zinc... If you have trouble getting KClO3/Mg to ignite then you should consider pruchasing/acquiring fresh batches of both chemicals.
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nitro-genes
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Could be the "fineness" of your Mg, although when it is a dark grey powder it should be fine enough. Another possibility is that it is heavily coated
somehow, inhibiting the reaction...
You can test your Mg powder by adding a little conc. NaOH solution to a VERY SMALL amount of the Mg powder. If the mix immediately starts to boil and
evolve a lot of heat, leaving no impurities behind in the solution when the reaction subsides it is unlikely that it is coated or oxidised somehow....
If you doubt the potassium chlorate, you could add a drop of conc. sulferic acid to a small pile of it. If is starts to make small popping and hissing
sounds and evolve chlorine smelling gasses (ClO2) its likely that it at least contains some potassium chlorate...
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12AX7
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NaOH and Mg??? Al sure, but, I'm confused.
Acid will certainly do to make either into a voluminous, bubbly, hot, corrosive mess (and especially with copper ions present)! 
Tim
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Zinc
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| Quote: | Originally posted by nitro-genes Another possibility is that it is heavily coated somehow, inhibiting the reaction...
If you doubt the potassium chlorate, you could add a drop of conc. sulferic acid to a small pile of it. If is starts to make small popping and hissing
sounds and evolve chlorine smelling gasses (ClO2) its likely that it at least contains some potassium chlorate... |
I mixed some KCLO3 and sugar and to the mixture i added a few drops of conc.H2SO4. When a drop would hit the pile a "ssssssss" sound would be heared
and the place where the drop landed would be charred but it would not ignite.
I also tested the Mg in a mixture of it with KMnO4. I ignited it with a propane/butane torch and it burned very quickly.
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Zinc
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20 minutes ago I tried to light a mixture of KBrO3 and activated carbon with a magnesium ribbon. Unfortunatly the mixture didn't burn. I am sure that
the KBrO3 is KBrO3. I heated it until it decomposed to KBr and oxygen and the I added the potassium bromide to conc. H2SO4 and fumes of HBr were
evolved. Also the H2SO4 turned red from a small quantity of bromine that was evolved. Anyway it seems that I must aquire some new KBrO3 and KClO3 but
I am still want to know why the mixtures woul'd not burn. The reactants were wery fine and toroughly mixed. The KClO3 and KBrO3 were very old (20-30
years) bute never opened before abd were sealed very well. So do KBrO3 and KClO3 have a limited shelf life?
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woelen
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I have KClO3 of 25 years old, it was opened up before many times and it still is VERY active. On mixing with red P it explodes, simply by rubbing it
with a little stick. Adding H2SO4 results in formation of yellow ClO2 and mixing it with sulphur gives a very sensitive and brightly buring mix.
As far as I know, both KClO3 and KBrO3 have unlimited shelf life, provided they are stored in a dry place.
The KBrO3 you have may be a mix of KBr and KBrO3 in a 5 : 1 molar ratio. Such a mix is quite common, because it provides a very convenient way of
making bromine in acidic aqueous solution, simply by adding the solid to it. Try adding some of your solid to dilute sulphuric acid. If you
get copious amounts of bromine, then your chemical indeed is a mix of KBrO3 and KBr. If it was sold as such, then of course it also must be on the
label.
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MadHatter
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KClO3/Sucrose/H2SO4
Sounds like there's something wrong with the KClO3. A drop of concentrated sulphuric acid
placed on a pile of KClO3/sugar should cause that mixture to flare up and burn.
From opening of NCIS New Orleans - It goes a BOOM ! BOOM ! BOOM ! MUHAHAHAHAHAHAHA !
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Zinc
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| Quote: | Originally posted by woelen
The KBrO3 you have may be a mix of KBr and KBrO3 in a 5 : 1 molar ratio. Such a mix is quite common, because it provides a very convenient way of
making bromine in acidic aqueous solution, simply by adding the solid to it. Try adding some of your solid to dilute sulphuric acid. If you
get copious amounts of bromine, then your chemical indeed is a mix of KBrO3 and KBr. If it was sold as such, then of course it also must be on the
label. |
To 30 ml of dilute sulfuric acid (battery acid) I added a small spoon of of KBrO3. the KBrO3 just dissolved. No bromine was evolved. Also no other gas
was evolved. So it seems that it is pure potassium bromate.
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garage chemist
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Seems like there's something wrong with your mixing.
You have to powder both components separately with mortar and pestle, until they are as fine as dust. Then you can mix them by shaking together in a
film can.
Also, what mixing ratios did you use? You have to weigh the components.
Also, activated carbon is absolutely useless for pyrotechnics. It doesn't burn when mixed with oxidisers!
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Zinc
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| Quote: | Originally posted by garage chemist
Seems like there's something wrong with your mixing.
You have to powder both components separately with mortar and pestle, until they are as fine as dust. Then you can mix them by shaking together in a
film can.
Also, what mixing ratios did you use? You have to weigh the components.
Also, activated carbon is absolutely useless for pyrotechnics. It doesn't burn when mixed with oxidisers! |
I powder the reactants by putting them on a paper and pressing them hard with a spoon until they are fine as flour.
I mix them via the diaper method.
For ratios I dont know. I never measure anything. Every pyrotehnic mixture I have ever made in my life was mixed with out any standard ratios but that
method has never failed me. Some mixtures were good and some not but no mixture has ever failed to ignite when made by this method so I doubt that
something is wrong with my mixing.
About the activated carbon I agree. I once mixed it with KMnO4 and it burned very slow and a lot of solid residue was left.
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woelen
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| Quote: | Originally posted by Zinc
To 30 ml of dilute sulfuric acid (battery acid) I added a small spoon of of KBrO3. the KBrO3 just dissolved. No bromine was evolved. Also no other gas
was evolved. So it seems that it is pure potassium bromate. |
Good, now we for sure know it is not a mix of KBr and KBrO3. This test is not 100% conclusive. It could be pure KBrO3, or pure KBr. Now add some of
the solid to conc. HCl (or add some NaCl to your solution in battery acid). If you get production of gas (chlorine) and/or creation of bromine (yellow
or even red color of liquid), then you have pure KBrO3, otherwise you have pure KBr.
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woelen
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Zinc, after reading all things over again, I have the strong impression that you have received pure KCl and pure KBr. These compounds are called
"kalium chloratum" and "kalium bromatum" in pharmacies language, which was not uncommon for chemicals 30 years ago. This is VERY misleading, because
these names stand for the chloride and bromide, and NOT for the chlorate and bromate.
All the hissing and fizzling you have with H2SO4 simply is formation of HCl and HBr. With the bromide you have a side reaction, where some bromine is
formed, due to the oxidizing properties of conc. H2SO4. The charring of the sugar, also is the action of H2SO4 on sugar. I did a test of adding some
H2SO4 to my KClO3. It forms a red/orange drop and yellow fumes of ClO2 are emitted. When I added some sugar to this, then it exploded with a high
pitched PENG  . This is quite different from what you have, just charring of the
sugar!
So, I'm afraid I have to disappoint you, but I really think you have pure KCl and pure KBr.
[Edited on 11-7-06 by woelen]
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Zinc
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| Quote: | Originally posted by woelen
Zinc, after reading all things over again, I have the strong impression that you have received pure KCl and pure KBr. These compounds are called
"kalium chloratum" and "kalium bromatum" in pharmacies language, which was not uncommon for chemicals 30 years ago. This is VERY misleading, because
these names stand for the chloride and bromide, and NOT for the chlorate and bromate.
So, I'm afraid I have to disappoint you, but I really think you have pure KCl and pure KBr.
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I don't think so. When I mixed the potassium chlorate with sulfur (a dangerous thing to do) it burned good so it can't be KCl. Sadly it only burned
good with sulfur. And about the potassium bromate when I added the potassium
bromate to dilute sulfuric acid it only dissolved. No HBr was evolved. I also heated the KBrO3 until it decomposed to potassium bromide and oxygen.
Then I added the KBr to conc. H2SO4 and fumes of HBr were evolved. Also the sulfuric acid turned red from a small amount of bromine that was also
evolved. From this I conclude that I have KBrO3 and KClO3 and not KBr and KCL.
You are right about the old pharmacy names. Once in school I have seen a bottle and on the lable it wrote ammonium chloratum. I then said "No way.
This can't be ammonium chlorate. It is a very sensitive explosive." Afther that I saw the formula NH4Cl under the name.
Edit
| Quote: | Originally posted by woelen
Now add some of the solid to conc. HCl (or add some NaCl to your solution in battery acid). If you get production of gas (chlorine) and/or creation of
bromine (yellow or even red color of liquid), then you have pure KBrO3, otherwise you have pure KBr. |
I added some NaCl to the battery acid and after that I added some of the supposed KBrO3. Nothing happened. The supposed KBrO3 only dissolved. I still
think that I have KBrO3 and not KBr. When I added the KBrO3 to dilute H2SO4 it would just dissolve but when I heated the KBrO3 until it would
decompose to oxygen and KBr and added the potassium bromide to dilute sulfuric acid fumes of HBr were evolved. Also the H2SO4 turned red from a small
amount of bromine that was also evolved.
[Edited on 11-7-2006 by Zinc]
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chromium
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I have one more idea how to distinguish between KBr and KBrO3. KBrO3 is much less soluble in water: 6.9g/100ml @ 20C ; 3.0g/100ml @ 0C. KBr: 65.2
g/100ml @20C ; 53.5 g/100ml @ 0C
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woelen
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I have severe doubts on your KBrO3. I have KBrO3 and I added some to H2SO4. Added to dilute H2SO4, it just dissolves, but KBr also just dissolves and
no fumes of whatever type are evolved. When I add solid KBrO3 is added to concentrated H2SO4 then a VERY violent reaction starts, producing oxygen and
bromine.
Pure KBr, besides HCl, also gives bromine (and SO2) with conc. H2SO4, because of the oxidizing properties of conc. H2SO4.
And, when you have KBrO3, even only at low percentage, then adding this to a NaCl/H2SO4 solution definitely would give a fairly violent reaction, in
which chlorine and brominechloride are formed. I did the experiment by adding solid KBrO3 to 15% HCl. When this is done, then there is strong
effervescence at the granules of KBrO3. The fizzling is quite strong. The bubbles are chlorine, but also contain bromine. The color is yellow. The
liquid also becomes yellow (*piss color*). When you could not even see a faint yellow color, then I'm very sure that your stuff is not KBrO3.
You write that you heated the KBrO3, until it decomposes, giving oxygen. Did you test the presence of oxygen with a glowing spint?
If you really want to be sure, and you have conc. HCl, then add a spatula full of both of your chems to that.
KClO3 will give a very intensely colored deep yellow gas, and the liquid becomes deep yellow. Even with a small amount of KClO3 you will see that
color. Pictures of what you should observe are here:
http://woelen.scheikunde.net/science/chem/exps/clo2/index.ht...
KBrO3 will result in violent bubbling, formation of chlorine gas, and the liquid will turn piss yellow. Unmistakenly!
If your liquid remains colorless and no bubbles are observed, then 100% sure you have no KClO3 and KBrO3.
If you don't have concentrated HCl, then you could try adding a lot of finely crunched table salt to 30% H2SO4 and use that instead of conc. HCl.
[Edited on 11-7-06 by woelen]
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Zinc
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| Quote: | Originally posted by woelen I have KBrO3 and I added some to H2SO4. Added to dilute H2SO4, it just dissolves, but KBr also just dissolves and
no fumes of whatever type are evolved. When I add solid KBrO3 is added to concentrated H2SO4 then a VERY violent reaction starts, producing oxygen and
bromine.
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When I added the KBr made by the decomposition of KBrO3 I added it to conc.H2SO4 and not to dilute H2SO4. I will add it to dilute H2SO4 and post the
resluts.
| Quote: | Originally posted by woelen
And, when you have KBrO3, even only at low percentage, then adding this to a NaCl/H2SO4 solution definitely would give a fairly violent reaction, in
which chlorine and brominechloride are formed.
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Nothing happened. The KBrO3 just dissolved. Do you mean a mixture of NaCl and conc.H2SO4 or a mixture of NaCl and dilute H2SO4? I added it to a
mixture of dilute H2SO4 and NaCl.
| Quote: | Originally posted by woelen
I did the experiment by adding solid KBrO3 to 15% HCl. When this is done, then there is strong effervescence at the granules of KBrO3. The fizzling is
quite strong. The bubbles are chlorine, but also contain bromine. The color is yellow. The liquid also becomes yellow (*piss color*). When you could
not even see a faint yellow color, then I'm very sure that your stuff is not KBrO3.
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I added a small spon of KBrO3 to 19% HCl and nothing happened. The KBrO3 just dissolved.
| Quote: | Originally posted by woelen
You write that you heated the KBrO3, until it decomposes, giving oxygen. Did you test the presence of oxygen with a glowing spint?
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The glowing splint didn't ignite. It even stopped to glow.
Also in my previous posts I have forgot to mention that when I was heating the potassium bromate when it decomposed (the cracking sound stopped) the
christals melted.
I also added the KBrO3 to conc.H2SO4 and a violent reaction occured. The H2SO4 turned red and fumes of bromine were evolved. Also a small amount of
"dilute" white fumes was evolved.
[Edited on 11-7-2006 by Zinc]
[Edited on 11-7-2006 by Zinc]
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Zinc
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| Quote: | Originally posted by Zinc
When I added the KBr made by the decomposition of KBrO3 I added it to conc.H2SO4 and not to dilute H2SO4. I will add it to dilute H2SO4 and post the
resluts.
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I tried it 10 minutes ago. It dissolved and a smell simillar to the smell of HBr appeared. No visible fumes were evolved and no bubling occured.
Unfortunatly I can't more experiment with potassium chlorate. I ran out of it and
noticed it today when I took the botlte and saw it is empty.
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woelen
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OK, now I'm 100% sure you have no KBrO3, you have KBr .
The crackling sound on heating is due to crystals, breaking apart. Even simple table salt may give crackling noise on strong heating.
I indeed meant adding KBrO3 to dilute H2SO4/NaCl. You did that and nothing happened, just dissolving. Even if your stuff contained a few percent of
KBrO3, then the liquid would turn yellow or even red/orange.
Finally, you added it to 19% HCl. My KBrO3 gives a very violent bubbling reaction with this, similar to adding Na2CO3 to 19% HCl, except that the gas
evolved is not CO2, but Cl2.
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Zinc
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It was probably a old pharmacy name. They called ammonium chloride ammonium chloratum so probably they called potassium bromide potassium bromatum.
I really hate those old pharmacy names. They are very misleading.
About the KClO3 I don't know. Probbably it was potassium chlorate since it burned good with sulfur. Sadly it burned good only with sulfur. Do you know
the reason why it burned good only with sulfur? It didn't burn with Mg and with activated carbon it burned very slow and only a part of the pile would
burn away. The rest of the pile remained. Unfortunatly I can't experiment more with KClO3 since I have run out of it.
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woelen
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The only reason I can think of with the KClO3 failing to burn with Mg is that it is not mixed well enough. Normally, it definitely reacts violently,
but the metal must be finely powdered. Not granules of 0.1 mm size, but much smaller, such that they seem to float in the air, when they are gently
breathed at.
Yes, with the KBr I can imagine that the person, who gave it to you was mislead by the name of the compound. You can, however, fairly easily make
KBrO3 from KBr by means of electrolysis. I have done that (in fact, that is my source of KBrO3), and garage chemist also has done that. Fairly
recently, there was a thread about that, just search for "bromate", or something like that. Garage chemist used a tiny amount of a dichromate, to make
the electrolysis cell more efficient and that indeed is a good idea. If you have some, give it a try, but without, it also works, but with much lower
efficiency. Garage chemist obtained really white KBrO3, mine is a little yellow, probably due to trapped traces of Br2. It works very well though,
despite the slight coloration of the chemical.
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Zinc
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| Quote: | Originally posted by woelen
Normally, it definitely reacts violently, but the metal must be finely powdered. Not granules of 0.1 mm size, but much smaller, such that they seem to
float in the air, when they are gently breathed at.
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You are probbably right. My magnesium was not airfloat. Unfortunatly I have not a ball mill.
But still I don't understant why it didn't burn when I mixed it with sugar and added a drop of conc.H2SO4. The place where the drop landed charred
and a "ssssss"sound was heard but the mixture didn't ignite.
A word of warning to everyone who is working with bromates. They are carcinogenic. http://en.wikipedia.org/wiki/Bromate
BTW you have a very good web page woelen.
[Edited on 11-7-2006 by Zinc]
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