KMnO4 + S===}?

[simply RED]

This is very useful mixture( 2 parts KMnO4, 1 part S in volume). It burns fast and creates about 800 degrees celsius. I¡¦ve used it for many applications, from rockets to CO2 cartridge cratermakers. It is ignited when 98%H2SO4 drops on it, I¡¦m sure everyone here is expert on it ƒº. But I doubt what is the real chemical reaction that takes place during its burning.
I think it is something allike:
2KMnO4 + 5S = K2SO4 + 2MnS+ 2SO2
or when the quantity of the sulphur is lower:
2KMnO4 + 2S=K2SO4+ MnO +SO2
What do you think?

[PHILOU Zrealone]

To help you on this we need the parts in weights!!!
Volumes are too variable...also I think it has been discussed less than 2 month ago!

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"Life that deadly disease sexually transmitted".
"Chemistry is all what stinks and explode; Physic is all what never works! ;-p :-) :o)"

[simply RED]

Immagine I mix the KMnO4 and the sulphur in 2:5 molar proportion. That means:
M(KMnO4) is 39+55+16.4=158
Ar(S)=32
158.2=316
32.5=160
316/160=2
2 parts KMnO4, 1 part sulphur in weight.
Will the upper reaction:
(2KMnO4+5S=K2SO4+2MnS+2SO2) take place when I ignite it?

[PHILOU Zrealone]

2KMnO4 + 5S --> 2MnO2 + K2O + SO2 + 4S
Here you would have an excess of S!
Changing the ratios might induce slightly different products of reaction but usually the more stable products (oxydes here) are formed!
I would never expect sulfur to displace oxygen from an oxyde since sulfur is less electronegative than oxygen!
This is proven by
CuSO4 + heat --> CuO + SO2 + 1/2O2
the reaction is not
CuSO4 + heat --> CuS + 2O2
otherwise all sulfates would be good oxydisers what is never the case (except with very powerful reducers!).

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"Life that deadly disease sexually transmitted".
"Chemistry is all what stinks and explode; Physic is all what never works! ;-p :-) :o)"

[simply RED]

I made an experiment:
I ignited some mixture of KMnO4 and S. Then I got the solid that is left after the burning and mixed it with some water. Some of it dissolved and some remained a precipitate(some of it got to coloid disperse phase). Then I mixed the solution with 60% nitric acid. H2S gas formed immediately and it started to smell like bad eggs(U know how it smells). I don't know why but some sulfide compound forms anyway. If you don't believe this, try it at home, very easy.
Ilustration of the reaction of the H2S giving off.
A2+ + S2- + 2H+=H2S +A2+
AS is the sulphide.(A- imaginary 2 valent element)

[Anthony]

I think the Al and S combine on burning to form aluminium sulphide (AlS?), when mixed with a mineral acid H2S.

[PHILOU Zrealone]

Yes a little of MnS, Mn2S3 and MnS2 can be formed due to the fact that any chemical reaction is not 100% complete...there is always a little percentage of side reaction... and a very little % of H2S can be smell!

Imagine a little H2O inside your mix...
H2O + S2+ heat <==> H2S + SO
H2S + K2O --> K2S + H2O
K2S + 2HNO3 --> 2KNO3 + H2S

Also by the way SO2 solution smells a bit like rotten eggs!
And K2O + SO2 --> K2SO3
K2SO3 + 2HNO3 --> 2KNO3 + H2O + SO2

Your only possibility to be sure of what happens is to make a titration of the H2S! (by precipitation of a very unsoluble sulfide!).
Ahh yes, btw, when you mix things and set fire to them, the % in the mix can influence the reaction products; but the heat of the reaction also and this last one can be influenced by the amount of mix that is burned!

4Al + 3S2 --> 2Al2S3
Al2S3 + 3H2O --> Al2O3 + 3 H2S
Al2O3 + 3H2O --> 2Al(OH)3



------------------
"Life that deadly disease sexually transmitted".
"Chemistry is all what stinks and explode; Physic is all what never works! ;-p :-) :o)"

[simply RED]

It will be good to measure the pH of the solution. If K2O forms in big quantities it will be highly basic(pH>7). It is very bad I haven't got phenol phatalein or limus paper to measure it.

[This message has been edited by simply RED (edited May 28, 2001).]

[Demolition]

Tonight I experimented with some KMnO4 and S,I mixed it in a ration of 2 parts KMnO4 to 1 part S.Here are some photos I took.
http://us.f1.yahoofs.com/users/778c11ca/bc/My+Documents/1.gif?bcc4_Z7Akroaz9mD
15 grams of powder being mixed(not grinded)
http://us.f1.yahoofs.com/users/778c11ca/bc/My+Documents/2.gif?bcc4_Z7AxXynJAqO
5-7 grams of Powder
http://us.f1.yahoofs.com/users/778c11ca/bc/My+Documents/3.gif?bcc4_Z7AUYyMRR3e
Starting
http://us.f1.yahoofs.com/users/778c11ca/bc/My+Documents/4.gif?bcc4_Z7A4sm41NjN
Starting


[This message has been edited by Demolition (edited June 01, 2001).]

[Demolition]

http://us.f1.yahoofs.com/users/778c11ca/bc/My+Documents/5.gif?bcc4_Z7A13IyxQpw
Warming up now!
http://us.f1.yahoofs.com/users/778c11ca/bc/My+Documents/6.gif?bcc4_Z7AeUN3U9Do
Going well now http://theforum.virtualave.net/ubb/smilies/biggrin.gif
http://us.f1.yahoofs.com/users/778c11ca/bc/My+Documents/7.gif?bcc4_Z7A6EMLtj04
Starting to slow up http://theforum.virtualave.net/ubb/smilies/tongue.gif

I recommend this LE. http://theforum.virtualave.net/ubb/smilies/smile.gif

(hope the pics work)
(sweet,they did http://theforum.virtualave.net/ubb/smilies/tongue.gif)
Demolition

[the freshmaker]

sorry Demolition, but your pics doesn't workhttp://theforum.virtualave.net/ubb/smilies/rolleyes.gif

[Demolition]

Sorry guys(and girls).They seem to work fine on my computer all the time.I uploaded them to my Yahoo Briefcase and then linked them from there.Any ideas what's wrong or does anyone know a better place to upload them(I tried Angelfire but I couldn't seem to get it to work)
Demolition

[This message has been edited by Demolition (edited June 02, 2001).]

[BrAiNFeVeR]

I can't get my Yahoo briefcase pics to work either ;-( . Naturally you need to share them, so i did, but when i tried it in a forum, it still did not work ...

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"Mess with me, and you'll end up with a .44 under your chin and your brains on the ceiling"

[This message has been edited by BrAiNFeVeR (edited August 01, 2001).]

[Mick]

......

<small>[ June 13, 2002, 03:18 AM: Message edited by: Mick ]</small>