Entropy & Osmosis: Brownian Motion & 2nd Law of Motion

In summary, diffusion of a substance from an area of high concentration to an area of lower concentration will increase the entropy of the system. Thermo-osmosis can also play a role in this process, as it can increase the entropy of a system by allowing small objects to move between areas with different entropy levels. However, this process can also be harnessed by using a lever to convert osmotic potential energy into gravitational potential energy. Maxwell was right- there can be a demon, even in a small case.
  • #1
menniandscience
99
2
what exactly browian motion and osmosis does to the second law of motion? nothing right? because anyway one will set an experiment trying to locate semipermeable membrane, he\she already exert more energy.

(i need you to verify me)
thanks
 
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  • #2
Diffusion of a substance from an area of high concentration to an area of lower concentration will increase the entropy of the system.

Brownian motion is tricky to talk about in terms of entropy. Brownian motion (the random walk of particles) is something that occurs with single particles. Entropy, a thermodynamic concept, applies to large ensembles of particles, not single particles. Of course, the Brownian motion of large ensembles of particles is diffusion.
 
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  • #3
I think you need to also consider thermo-osmosis. Or that, in a permeable membrane which has some sort of an entropy/temperature gradient, particles will always diffuse towards higher entropy since it is thermodynamically favored.
 
  • #4
well it is a difussion if the membrane got holes alowing only small objects move both sides and big stay in one side. you build a pressure, when you remove the membrane there is energy, and that is not just a few particles but a large quantity of microscopic particles
 
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  • #5
and Maxwell was right, there can be a demon, even if it is in a small case
 
  • #6
meni ohana said:
if the membrane got holes alowing only small objects move both sides and big stay in one side. you build a pressure, when you remove the membrane there is energy [...] and Maxwell was right, there can be a demon, even if it is in a small case
The membrane is just a lever for converting the osmotic potential energy (that you prepared) into gravitational potential energy (which you know how to harness). You can tell that it isn't creating energy by the fact that, unlike Maxwell's demon, the operation of your device can't repeat in a closed cycle (you have to perform more work to separate back the solutes first).
 

1. What is entropy and how does it relate to osmosis?

Entropy is a measure of the disorder or randomness in a system. In the context of osmosis, it is related to the movement of molecules from an area of high concentration to an area of low concentration. As molecules move, they become more randomly distributed, increasing the entropy of the system.

2. What is Brownian motion and how does it contribute to entropy?

Brownian motion is the random movement of particles suspended in a fluid, caused by collisions with other particles. This motion contributes to the increase in entropy by constantly redistributing particles and increasing their disorder.

3. How does the 2nd law of thermodynamics relate to entropy and osmosis?

The 2nd law of thermodynamics states that the total entropy of a closed system will always increase over time. In the case of osmosis, as particles move from an area of high concentration to an area of low concentration, the system becomes more disordered, increasing its entropy in accordance with the 2nd law.

4. Can the movement of molecules through a selectively permeable membrane be predicted using entropy?

While entropy plays a role in the movement of molecules through a selectively permeable membrane, it is not the only factor that determines the direction of osmosis. Other factors such as concentration gradients and the properties of the membrane also play a role.

5. How is the concept of entropy and osmosis applied in real-world situations?

The concept of entropy and osmosis has many practical applications, such as in water purification and desalination processes, as well as in the functioning of cells in living organisms. Understanding these concepts allows us to manipulate and control the movement of molecules for various purposes.

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