Since entropy always rises, does water always tend towards steam?

Question

Check this Y!A question, and answers given:

http://answers.yahoo.com/question/index;_ylt=AkFArk4L1x8uHPl5s8Gn5Sz4xQt.;_ylv=3?qid=20071231132048AAHdMVO

It's argued that steam has "higher disorder" than water, so is it reasonable to infer that, therefore, standing water will naturally turn into steam? No, please don't argue that entropy is energy, and it takes energy to produce more entropy.

Charlie149, even if you put work into a closed system, the total entropy will still nonethless rise. I think you're referring to refrigeration, as an example.

WhatWasThatNameAgain, I thought things just "naturally" become more disordered without anything being done to them? Many believe that the 2nd Law of Thermodynamics is a statement (proof, they even believe) that things ALWAYS become more disordered. So, if steam is more disordered than standing water, why isn't standing water turning into steam?

mentisthemagnificent, a little thermodynamic physics for you: The entropy of a non-equilibrum system can continue to rise even though its total energy remains constant.

Aw that's not fair, WOMBAT, we know that vapor from evaporated water is "steam", but you're side-stepping the spirit of this question. Nobody ever got scalded by cold water evaporating from a cup of it.

falsoon, in fact, once a closed system reaches equilibrum, its entropy becomes constant. Entropy rises for a closed system only if it's in a non-equilibrum state. However, very interesting ordering or patterns can develop in a closed system that is in a non-equilibrum state, such as the BZ reactions in chemistry, which looks far from "increasing disorder".

So, Ω Remo Aviron, are you suggesting that a system left "open" can have a *decreasing* entropy, and therefore less disorder? Open systems can produce order? How about that?

See my next posted question:

http://answers.yahoo.com/question/index;_ylt=AkSskmwTrgtZSzQGxyuzupXsy6IX;_ylv=3?qid=20071231232421AAzKKK6

Answer 1

In a closed system. You reach equilibrum temperature and pressure and that's it. From that point forward, no change in net entropy. Water will tend to steam, but an equal amount of steam will tend to water. Otherwise, temperature and pressue would not stay constant.

But left to its own, in an open system, water would turn to ice, not steam.

In an open system, everything tends to a state of lower, not higher entropy and energy. An open system radiates its energy away. It is only the dynamic influx of heat from other objects trying to get rid of their energy (i.e, the sun, the earth's core, matter with chemical or thermal potential, etc) that keeps the system's water from freezing and the world in overall rough balance.

Yes, I realize that entropy can rise with no change in overall energy for a system, but to keep the overall energy in a system constant, you need an influx of energy to offset energy the black body energy radiated away (even if just radiated to the container sides). And yes, I am ignoring all of my thermal courses, but that was so long ago that I am entitled to either ignore or forget them.

Answer 2

The fact that entropy increases in a closed system,
is applicable only to so-called "irreversible processes".
But water-to-steam is a reversible process,
so is this the answer to your question?
Would not the entropy be in a state of flux,
increasing and decreasing, until some sort of
established entropic equilibrium ensued, which
I'm now going to have to call my "4E hypothesis"?

Answer 3

Well, lets consider a closed, insulated steel tank containing liquid water and water vapor.

If some of the water were to vaporize, it would increase the pressure, thus increasing the "internal energy" of the steam, as compared to the water. If the pressure were to increase beyond the vapor pressure of water at room temperature, then this would cause the total entropy to *decrease*, not increase.

As others have pointed out, an open glass of water will obviously evaporate. This is not exactly a "closed system."

Also, since in dry air, the "partial pressure" of water vapor is less than the vapor pressure of the liquid, the liquid water has more internal energy than the ambient vapor. Thus, evaporation will increase the entropy of the universe.

Edit:
Haw, haw, very funny.......;-P

Answer 4

Entropy is a winding down, and steam is a winding up. Ice is entropic water. It does not take energy to create entropy. It takes a lack of energy. Entropy is a loss of energy. It is usually also accompanied by a loss of order...but not always. After the heat death of the universe-towards which all entropy is leading-all will be ice.

Answer 5

Steam has more entropy, but you had to add energy (heat) to get it to that state (at least in normal atmospheric conditions).

In normal conditions, water won't just turn into steam, because it takes energy to do this#.

However, if you put out a glass of water in a dry climate, the water will "evaporate" over time. Showing that it will slowly go to the state of higher entropy.

Answer 6

Entropy does not always rise. If you put work into a system, entropy can decrease.

What is the system you are talking about? The whole Universe?