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What happens to the heat?

by Interception
Tags: heat
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Interception
#1
Apr10-12, 09:35 PM
P: 15
Ok, so this may be more of a chemistry oriented question, but physics is pretty much the foundation of chemistry. We've covered thermochemistry to some extent in my Properties of General Chem class, and I had a thought. Since heat is associated with the random motion of atoms and molecules within a substance or state of matter, suppose I had a piece of metal heated to a specific temperature (not really important what temperature but let's say around 100* Celsius) suspended in an evacuated isolated system (I have no idea how it would be suspended, so long as it is not in contact with any other surface, so just assume it is). Would the temperature of the metal drop? There are no gas molecules within the system for the heat to be transfered to, and it is not in contact with anything else. Would the average kinetic energy of the molecules begin to slow over time due to intermolecular forces? This is just out of curiousity, and I apologize if it sounds rediculous.
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anuragkanase
#2
Apr11-12, 01:04 AM
P: 27
Is this what you mean to say:
You suspend a metal in a vacuum isolated jar(say), so, does the metal cool?

If that's what you wish to say, the answer is yes. It would definitely drop. And it is due to Radiation.
gomunkul51
#3
Apr11-12, 07:26 PM
P: 275
Excellent question!
The fact of the matter is that anything with temperature higher than absolute zero (0 kelvin) will loose heat to the surroundings via thermal radiation (electromagnetic radiation due to non-zero temperature).

http://en.wikipedia.org/wiki/Thermal_radiation


Roman.

haruspex
#4
Apr12-12, 02:32 AM
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What happens to the heat?

Because you specified a metal object, it will certainly radiate energy. But it will also absorb energy radiated from its surroundings, so if they're at the same temperature it is unlikely to cool.
For other materials it gets more complex. A ball of nitrogen gas in space, hanging together by gravitational attraction, would have great difficulty emitting anything unless molecules in it reach sufficient energy to knock electrons into excited states.
The difference is all those free electrons buzzing around in metals, ready to emit at the slightest acceleration.


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