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Question

Summarize the processes by which water changes from on state to another. Indicate whether heat energy is absorbed or liberated.

Answer 1

Evaporation or boiling (liquid -> gas) absorbs heat

Condensation (gas -> liquid) liberates heat

Thawing (solid -> liquid) absorbs heat

Freezing (liquid-> solid) liberates heat

Sublimation (solid-> gas) absorbs heat

Deposition (gas -> solid) liberates heat

(an example of deposition, which is the opposite of sublimation, is the formation of frost)

http://id.mind.net/~zona/mstm/physics/me...

The key point to get here is that these are all state changes, and changing state always involves a certain amount of energy that is not accounted for in a simple temperature change. In other words, it takes more heat to change water from 100 degrees Celsius to 101 degrees Celsius as steam than it does to change water from 99 degrees C to 100 C. The reverse is true going the other direction.

Answer 2

As water heats up and some heat fluxes starts to Begin making steam (water vapor) the closer the water gets to boiling point the more stream it lets out- this is water in the gas state.

When stream or vapor condensates (air pressures rises and temperature gets cooler) it comes back as rain.

If the temperature drops to freezing point 0 degrees C the water becomes a solid.