Endothermic flame???

[pigeon_soup]

hi

 

i am interested in wither or not a cold flame is possable, i concluded that were it possable the flame would have to be endothermic (takes in heat energy from its surroundings) and despite researching through all the books at home at my old school and my colledge i found nothing on the subject, and so i turned to the internet for gidance and all i found was many pages on the quenching of a flame using an endothermic reaction.

 

thank you for any useful input on the matter.

[Mercedes Benzene]

A flame cannot be endothermic, because it is the results of an exothermic system. As something burns (in the case of a candle it's the wax), the energy excites the electrons in the material that will be burned. As the electrons fall back to ground state, they emit photons of light.

 

Sorry, but no wicked cool hollywood candles for you. :D

[ronthepon]

However, you could have something like that if you figure out exactly what a flame is.

 

Normally, a flame will be composed of gases and tiny particles, hot and thus glowing.

 

Suppose you had gases that were colder than the environment and yet glowing? Yes, that would be an endothermic flame.

 

It's easy to get the gases to be cold, but to get them to glow at low temperatures... is the question.

 

As merc said, all we need are excited atoms in the gas. That wouldn't be too difficult... supposing we went for non thermal methods of electron excitation, that would do the trick.

 

Mmmmm would like to see this one happen.... :D

[pigeon_soup]

wow thank you for you input guys, i posted this question on a couple more forums and the 1st replie was always the same as that of Merc, and the second almost always the same as ron's replie, hmmm... could the elcetrons be excited through a form of electrolisys? (sorry for any spelling errors) could a catilyst be used in a useful way to aid the exciteing of the electrons without a large increase in temprature.

[gribbon]

It's a tiny bit off topic, but interesting nevertheless, but are there any endothermic reactions which absorb massive amounts of heat in a short space of time? Such a rection could lead to an implosion, rather than an explosion, because an explosion is the result of hot gases expanding outwards rapidly, whereas an implosion would be caused by gases contracting rapidly. Alternatively, any reaction that absorbed vast amounts of any local atmosphere would have the same effect....that could be pretty cool....:) :)

 

I only know of one reaction that comes anywhere near doing this, and that occurs when you mix barium hydroxide and ammonium thiocyanate, which is strong enough to cause frost to collect on the beaker it is done in....but this is still along way from an "implosion".

[pigeon_soup]

hmmm that is also interesting... i dont know of any that would but my chemisty training expands to my GCSE's and the several A-level chemestry books that i read through my GCSE physics lessons, but i do know that when a neculear reaction occurs, eg neuclear weapons, Chernobyl, there is an implosion before the explosion, not of much help to you i know but interesting non the less

[Jay-qu]

What you need is some reaction to have a large activation energy, and then settle to a higher delta H after the reaction. Thus been a net endothermic reaction, but have a portion of the reaction where energy is actually released.

[eric l]

wow thank you for you input guys, i posted this question on a couple more forums and the 1st replie was always the same as that of Merc, and the second almost always the same as ron's replie, hmmm... could the elcetrons be excited through a form of electrolisys? (sorry for any spelling errors) could a catilyst be used in a useful way to aid the exciteing of the electrons without a large increase in temprature.

 

Looks like you re-invented neon light - although that does not involve electrolysis, only high tensions. And you can harldly call it a flame, either, because it will not start a similar reaction in surrounding matter (which is essentially what a flame does).

[Moontanman]

wow thank you for you input guys, i posted this question on a couple more forums and the 1st replie was always the same as that of Merc, and the second almost always the same as ron's replie, hmmm... could the elcetrons be excited through a form of electrolisys? (sorry for any spelling errors) could a catilyst be used in a useful way to aid the exciteing of the electrons without a large increase in temprature.

 

The closest thing i can see to a cold flame is the reaction that gives a lightning bug it's glow. It's a cold chemical reaction that gives off light. if you could cause that to occur

In a gas I guess tecnically it would be a cold flame but probably not what you are looking for.

 

michael

[gribbon]

but have a portion of the reaction where energy is actually released.

 

Released? That would be an exothermic reaction then wouldn't it? We're looking for a reaction that either absorbs a vast amount of heat or vast amount of nitrogen/oxygen/any other atmospheric gas aren't we? (Or it could be exothermic to begin with, but then absorb far far more than it gave out, if that's what you mean...)