Evaporation and condensation problem

In summary, the conversation discusses the concept of evaporation and condensation, specifically why water's temperature does not exceed 100 degrees Celsius when it boils. The conversation also touches on the correlation between the structure of water molecules and its energy, as well as the sensation of feeling cold after a warm bath due to evaporation. The conversation concludes by discussing the relationship between heat and temperature in the process of evaporation.
  • #1
Rocksta
2
0
Hi,

I'm now studying evaporation and condensation and I have a question.

Why even when water boils, its temperature doesn't exceed 100 C?
Where did the energy gotten from environment go? What was it used for?

Examining structure of water and vapour molecules are given as a hint, but I see no correlation between that energy case and structure of molecules.

Are there some rules concerning kinetic energy of a liquid?

Also - I think it's related - why people feel cold after warm bath?
Is it because our body gives heat to environment?
 
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  • #3


This is a tricky one to explain without giving it totally away.

If I've got the gist of the question right: What happens when you get some water to 100 c, does it all instantly turn to steam? What happens to the liquid?

hint: imagine a pan of boiling water without a lid left on the cooker.

What level are you studying at? And you are perfectly correct about the molecules they are both H2O and that is an awful hint.

:P Damn Pion gave the game away.
 
  • #4


Oh yes, Pion, thank you. I understand it now.

However, I still don't know the answer to the second question and I will probably get it on the test, so I'd be grateful if someone explained.
I thought it must have something to do with giving or getting heat, am I right?
 
  • #5


Rocksta said:
Oh yes, Pion, thank you. I understand it now.

However, I still don't know the answer to the second question and I will probably get it on the test, so I'd be grateful if someone explained.
I thought it must have something to do with giving or getting heat, am I right?

If you mean arising from a tub of warm water and feel the chill, then what you are feeling is evaporation. But what is evaporation? The escape of more energetic water molecules to the atmosphere?
 
  • #6
You are correct about heat, so long are you are not comfusing it with temperature :P

Back to the pan example: although the temperature stays at 100 c you are still putting in energy (heat) to change the 100 c liquid water to 100 c water vapour.

http://www.spiraxsarco.com/images/resources/steam-engineering-tutorials/2/2/fig_2_2_3.gif

(cant be bothered linking it) hooray for auto links!

if you look at this you can see that from A to B the temp rises. From B to C you are still adding energy but the temperature is the same as liquid ------> steam and from C onwards heat is still being added and the steam increases in temp.
 

Related to Evaporation and condensation problem

1. What is evaporation and condensation?

Evaporation and condensation are two processes involved in the water cycle. Evaporation is the process where liquid water is converted into water vapor through the addition of heat energy. Condensation is the opposite process, where water vapor turns back into liquid water due to the release of heat energy. Both processes are essential for the continuous circulation of water on Earth.

2. What factors affect the rate of evaporation and condensation?

The rate of evaporation and condensation depends on several factors. The main factor is temperature, as evaporation and condensation occur faster at higher temperatures. Wind speed and humidity levels also play a role, as wind can carry away water vapor and high humidity levels can slow down evaporation.

3. How does evaporation and condensation impact the environment?

Evaporation and condensation have a significant impact on the environment. Evaporation helps to cool the Earth's surface and regulate the overall temperature. It also plays a crucial role in the water cycle, which is essential for the survival of plants and animals. Condensation helps to form clouds and precipitation, which provide the Earth with fresh water.

4. Is evaporation and condensation a reversible process?

Yes, evaporation and condensation are reversible processes. When water evaporates, it turns into water vapor, and when the water vapor condenses, it turns back into liquid water. This cycle can continue indefinitely as long as there is a source of heat energy and water.

5. How can evaporation and condensation be used in practical applications?

Evaporation and condensation have many practical applications. One example is in the desalination of seawater, where saltwater is heated to evaporate the water, leaving behind the salt. The water vapor is then condensed back into liquid water, providing fresh water for human consumption. Evaporation and condensation are also used in refrigeration and air conditioning systems to regulate temperature.

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