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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: nj_bartel on July 30, 2009, 08:32:20 PM

Title: What does fire accomplish, if anything, that heat does not?
Post by: nj_bartel on July 30, 2009, 08:32:20 PM
For example, if you have a flame that burns pretty low, say 200 oC and you have a heat source that heats to 200 oC, is that flame going to be able to accomplish something that that heat source cannot?  Why?
Title: Re: What does fire accomplish, if anything, that heat does not?
Post by: Agent-X on July 31, 2009, 01:46:56 AM
Maybe add CO2?
The fuel will break down to CO2 and H2O.
The CO2 might eventually deposit carbon on a surface.

A flame is more direct than an electric plate.
Also, I wouldn't use electric heat for a test tube.
Title: Re: What does fire accomplish, if anything, that heat does not?
Post by: 408 on July 31, 2009, 01:52:51 AM
Initiation of radical reactions.

But if you mean for heating a flask, they are the same.
Title: Re: What does fire accomplish, if anything, that heat does not?
Post by: nj_bartel on July 31, 2009, 02:00:39 AM
Got it, thanks.  Didn't realize fire involved radical formation  :)
Title: Re: What does fire accomplish, if anything, that heat does not?
Post by: DrCMS on July 31, 2009, 05:54:21 AM
Quote from: nj_bartel on July 31, 2009, 02:00:39 AM
Didn't realize fire involved radical formation 

It does and that explains why powder and halon fire extinguishers are so efficient; they are radical scavengers and stop the fire chemistry rather than just removing oxygen.
Title: Re: What does fire accomplish, if anything, that heat does not?
Post by: typhoon2028 on July 31, 2009, 08:14:28 AM
It is possible to have a flame at 200C?
Title: Re: What does fire accomplish, if anything, that heat does not?
Post by: nj_bartel on July 31, 2009, 11:40:05 AM
Quote from: DrCMS on July 31, 2009, 05:54:21 AM
Quote from: nj_bartel on July 31, 2009, 02:00:39 AM
Didn't realize fire involved radical formation 

It does and that explains why powder and halon fire extinguishers are so efficient; they are radical scavengers and stop the fire chemistry rather than just removing oxygen.

Cool stuff, love real world apps  :P


I believe naptha burns somewhere around there