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Topic: Surface tension  (Read 1767 times)

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Offline Naaga

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Surface tension
« on: June 19, 2016, 10:14:24 AM »
Hey.

I have found this description of surface tension:

"A molecule in contact with a neighbor is in a lower state of energy than if it were alone (not in contact with a neighbor). The interior molecules have as many neighbors as they can possibly have, but the boundary molecules are missing neighbors (compared to interior molecules) and therefore have a higher energy. For the liquid to minimize its energy state, the number of higher energy boundary molecules must be minimized. The minimized quantity of boundary molecules results in a minimal surface area. As a result of surface area minimization, a surface will assume the smoothest shape it can."

But I don't understand what kind of energy it is ?

Offline Arkcon

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Re: Surface tension
« Reply #1 on: June 19, 2016, 11:19:26 AM »
What you have is a fairly good definition, but its not a perfect on, so I'm not surprised that you're confused.  To help you learn, lets try go improve what you have.

First of all, we have to try to understand why the energy is less when a molecule has more neighbors then when it doesn't.  That may be relatable with a formula, and the units in the formula will tell you the type of energy.  Failing that, you can just Nam the types of energy that you know, and see if we can work from there.

Give it a try, check your class notes or textbook, and see what you can learn.
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline Naaga

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Re: Surface tension
« Reply #2 on: June 21, 2016, 12:23:56 PM »
Well, I think it's Gibbs free energy, but is it because the entropy is lower for the water molecules in the middle ?

Or is it something else ?

Offline Arkcon

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Re: Surface tension
« Reply #3 on: June 21, 2016, 06:48:29 PM »
That's what I thought was being said in the question, yes.  You see how the more ordered = less entropy, so if heat, enthalpy says the same, Gibbs Free Energy must become smaller.
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

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