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Q & A: temperature and water

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Most recent answer: 01/02/2018
Q:
When water is heated, temperature of water raises, is it as a result of the supplied thermal energy makes every atom of the molecule to transition to higher energy level and falls back to ground state releasing the energy, if so does the bonding of Hydrogen with Oxygen remain intact or is the temperature due to intra molecular motion or any other phenomenon. If it is due to intra molecular motion why there is no temperature raise of the mist produced in ultrasonic humidifiers.
- NN (age 15)
Akron,OH,USA
A:

Warming water (or anything else) makes it spend a higher fraction of its time in higher-energy states. It takes a lot of energy to actually break the H-O bonds, so warming the water will increase the fraction of broken bonds, but even at the boiling point most bonds are intact.

I believe that the ultrasonic energy in those humidifiers is partly absorbed, warming the water slightly. When the droplets evaporate, however, that cools the water down. That's because it takes energy for the water molecules to break away from each other. It's the same reason why evaporating sweat cools you.

Mike W.


(published on 01/02/2018)

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