Sciencemadness Discussion Board - Oxygen Balancing Help...

Oxygen Balancing Help...

iceicebaby - 28-1-2010 at 02:48

To oxygen balance three things... What do I do... I figured out how to do it correctly for two substances using this formula...

OB = -1599.94/Molecular weight of compound * (2X + (Y/2) + M - Z)
X = Number of Carbon atoms
Y = Number of Hydrogen atoms
M = Number of metal atoms
Z = Number of Oxygen atoms

(AN) NH4NO3 OB: + 9.994
KNO3 OB: +47.4745
NM OB: - 39.317
NG OB: +3.52
ETN OB: +5.2958
AL OB: - 59.3 ( (-1599.94/26.98) * (1) is not corrrect? )
KClO4 OB: +46.19
KClO3 OB: +39.2

Divide the oxygen deficient OB by the positive to find the ratio for making an oxygen neutral mixture of the two.

PNNM = NM OB: -39.317 / KNO3 OB: +47.4745 = .828 KNO3 per 1 NM

Now, ignoring the fact that some of my oxygen balances are screwed up, is this the correct approach below?

KCLO3 OB: +13.055
NM OB: - 39.317

Say I have 20g KClO3, and 20g NM. The oxygen balance of equal weight KClO3/NM should be KClO3 - NM = -26.262?

If I double the KClO3 the oxygen balance should now be... -13.207... For this mix: 40g KClO3 + 20g NM.

And another... 80g KClO3 and 20g NM = +12.903 Oxygen Balance for that mix, then I can use the simple division...
AL -59.3 OB divided by KClO3(80g)/NM(20g) mix OB +12.903 = 1 part AL to 4.95 parts mix to balance...
Converting to percentages... 16.8% AL added to 80g KClO3 and 20g NM is oxygen balanced.

Or do I need to add a whole new layer of complexity that uses molar weights vs weight in grams too?

Below is my newer more correct (I hope...) oxygen balance table... Would appreciate some help correcting the last errors though. :/
AL OB: -59.3 or -89 *Unsure > Possibly pyro aluminum powder is 89% because of the carbon?
NH4NO3 OB: +19.98
NH4ClO4 +34
KNO3 OB: +47.4745
KClO3 OB: +26.11
KClO4 OB: +34.643
NaNO3 OB: +47
NaClO3 OB: +45
NM OB: - 39.317
NG OB: +3.52
NC OB: ?
ETN OB: +5.2958
PETN: -10.1
RDX OB: -21.6

[Edited on 28-1-2010 by iceicebaby]

[Edited on 28-1-2010 by iceicebaby]

woelen - 28-1-2010 at 04:24

Skip the idea of oxygen balance. Just write out equations and use molar ratios. A perfect oxygen balance is obtained if
- oxygen combines with carbon to CO2
- oxygen combines with hydrogen to H2O
- chlorine combines with hydrogen to HCl or with alkali metal to MCl
- sulphur combines with oxygen to SO3
- nitrogen becomes N2
- alkali metal can be regarded as confined in M2O
- earth alkali metal can be regarded as confined in MO
- phosphorus can be regarded as confined in P2O5

Making this a little bit more practical:

The compound NH3CH2CH2NH3(ClO4)2 (ethylene diammine perchlorate) has perfect oxygen balance. Decomposition can be written as

NH3CH2CH2NH3(ClO4)2 --> N2 + 2CO2 + 2HCl + 4H2O

A mix of 1 mole of sulphur, 1 mole of carbon and 2 moles of KNO3 has perfect oxygen balance:

S + C + 2KNO3 --> SO3 + CO2 + K2O + N2

These reaction equations are purely theoretic and used for computing good oxygen balance. They only reflect correct oxidation state of the compounds after the reaction. In reality no K2O will escape and certainly no SO3. K2SO4 will be formed instead. Besides that, there usually will be side reactions as well, such as formation of sulfite, formation of nitrite, formation of nitrogen oxides, formation of sulphur dioxide, etc. But these only are side reactions.

Another example: decomposition of NH4ClO4 (ammonium perchlorate)

Try to get all nitrogen as N2, all chlorine as HCl (no metals available, so only HCl remains as option) and all oxygen as H2O. When this is done, we see that there is too much oxygen, 5 atoms are left:

2NH4ClO4 --> N2 + 2HCl + 3H2O + 5[O]

In order to make a good oxygen balance you need to add reductors. E.g. adding one mole of S and one mole of C makes up for a perfect oxygen balance:

2NH4ClO4 + S + C --> N2 + 2HCl + 3H2O + SO3 + CO2

In reality you can expect the SO3 to escape as H2SO4.

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Also keep in mind a practical thing: perfect oxygen balance does not always give optimum results in terms of brisance, speed of burning or explosion force. Sometimes a little excess of oxidizer makes a mix more powerful, in other cases it might be better to have a slight excess of fuel. But in general you can say that if oxygen balance is perfect that one will not be too far off the optimum. So, when designing a powerful mix, one can start off from a point with perfect oxygen balance and from there one can make little excursions in either the direction of too much oxygen or too little oxygen to find the true optimum in terms of performance of the mix.

[Edited on 28-1-10 by woelen]

iceicebaby - 28-1-2010 at 05:02

I am thinking that the easiest thing would be just to buy a high speed camera and test the old fashioned way... LoL!

I am never going to figure out anything more complex than OB. I have never done chemistry at all.

[Edited on 28-1-2010 by iceicebaby]

hissingnoise - 28-1-2010 at 05:34

Quote:

I am thinking that the easiest thing would be just to buy a high speed camera and test the old fashioned way.

What?
Hasn't woelen explained the concept well enough for you?

simply RED - 28-1-2010 at 07:25

SO3 is too much

. Let it escape as SO2 and have a higher volume of gasses.

Bikemaster - 28-1-2010 at 07:34

You want to synthesis explosive and you don't ever know how to make stoichiometry... I think you need to have a better base because explosive is not a kid game...

woelen - 28-1-2010 at 07:47

Quote: Originally posted by iceicebaby

I am thinking that the easiest thing would be just to buy a high speed camera and test the old fashioned way... LoL!

I am never going to figure out anything more complex than OB. I have never done chemistry at all.

[Edited on 28-1-2010 by iceicebaby]

What do you want? Just a big bang or are you really interested in chemistry and designing optimal mixes? If you just want a big bang, then stay away from the home-made mixes and buy yourself some decent fire crackers. This all sounds somewhat k3wlish to me.

iceicebaby - 28-1-2010 at 12:51

Why buy m80's for packs of 20 for $100 when I can buy a pound of 3 micron dark aluminum and two pounds of potassium perchlorate for $25 bucks? It's much safer to mix that stuff than people think. A remote control mixing apparatus and some anti static spray... And no sulfur! IMO flash powder is still more dangerous than any secondary HE. I even have sources for professional fireworks shells, but the prices are ridiculous black market.

I need to get oxygen balances down to experiment with uncommonly used oxidizers like strontium, barium, etc... There is no documentation on them anywhere! And yes, I know how to do the three step flame, friction, and shock tests for things... And take precautions for some things spontaneously combusting. (Doing only half a gram at first.)

I don't even use peroxides anymore or primarys... They are just scary. I developed a way to det a secondary without them. (Involves one of the secondarys with high compression and heat with perfectly sealed containment in a 2000+ PSI burst casing.)

Sigh, I guess I can just continue to ask my chemist friend. "Oxygen balance this please..." He doesn't mind. :/

Quote: Originally posted by woelen

Quote: Originally posted by iceicebaby

[Edited on 28-1-2010 by iceicebaby]

hissingnoise - 28-1-2010 at 14:06

Quote:

Sigh, I guess I can just continue to ask my chemist friend. "Oxygen balance this please.

Woelen's post says all you need to know on OB - but you'll still pester your (unfortunate?) friend?

iceicebaby - 28-1-2010 at 17:22

I failed math 101...

Quote: Originally posted by hissingnoise

Quote:

Sigh, I guess I can just continue to ask my chemist friend. "Oxygen balance this please.

Woelen's post says all you need to know on OB - but you'll still pester your (unfortunate?) friend?

woelen - 28-1-2010 at 23:57

I have anothern feeling with this. I intend to call it lazyness. Yes, you have to put some effort in this stuff, it does not simply fly into your hand (or head). But if you are willing to invest some time and effort, then your work will become so much more interesting. Just fooling around with chems without real understanding anything can be dangerous, but it also does not sound like much fun to me. Get an understanding of stoichiometry and your things will become much more fun.

watson.fawkes - 29-1-2010 at 04:33

Quote: Originally posted by woelen

But if you are willing to invest some time and effort, then your work will become so much more interesting.

It will also make you smarter, something rather more valuable in the long term than a few bangs.