a sample of ice at -10 degree celsius is heated until it becomes steam at hundred degree Celsius. state the effect that the thermal energy has on there sample at each stage of heating.
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Answer:
The average kinetic energy stays constant overall (the lost energy is transformed into potential energy and released back into the system as heat, which becomes vibrational kinetic energy), even though the particles slow down.
However, their temperature and thus average kinetic energy does not change during the freezing.
(Molecular rotations essentially stop, and the molecules can't fly across the room, but the molecules vibrate more vigorously in place.)
Take for example a closed container of water where heat is extracted from it.
During any phase transition, the temperature is constant, because the two phases are in equilibrium with each other. As an added note, ordinary phase transitions are also at constant pressure.
Because melting point and freezing point describe the same transition of matter, in this case from liquid to solid (freezing) or equivalently, from solid to liquid (melting).
What you may not realize is that while water is freezing or melting, its temperature is not changing! It is stuck on 0 ∘C during the entire melting or freezing process. It is easier to see this for boiling points. if you put a thermometer in water and heat it, the temperature will rise until it reaches 100 ∘C, and then it starts boiling. And while it boils, it will stay at 100 ∘C! All the way until the water has all boiled away. Now if you could somehow trap the steam (gaseous water) and keep heating it, the steam could have a temperature higher than 100 ∘C.
At the melting point, however, there is enough thermal energy to start breaking those intermolecular forces. What we observe is that the temperature does not rise, but bonds are breaking and the solid starts to melt. Once all the solid melts, the temperature of the (now liquid) water can increase when thermal energy is added.