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Basic Osmotics

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Basic Osmotics

Postby 2810712 » Wed Mar 16, 2005 2:08 pm

Hi,
I know what osmotic is, but don't know why does the osmosis and diffusion occur ? ? ?
i.e. why are they sponteneous ? ? ? Do, they increase disorder, I don't think so. Is it energitically favoured , may be, request U all to discuss this.

thanks.

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Postby Poison » Wed Mar 16, 2005 5:03 pm

Osmosis and diffusion are results of concentration difference. No need for energy. Because this is a rule. I mean molecules move from more concentrated medium to less concentrated medium.
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Postby MrMistery » Wed Mar 16, 2005 9:05 pm

Yes Poison, in the case off difussion. In the case of osmosis water goes from the less concentrated environment intothe more concentrated one
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yeah but

Postby 2810712 » Thu Mar 17, 2005 6:07 am

Yeah , but in nature some facts are just observed facts eg. the angular momentum of electron is integral multiple of h/2[pi]. But, some observations can be explained , of which one is osmosis; osmosis is a process which should be thermodynamically favoured , what makes the molecules diffuse from higher conc. to lower conc. ? is energy released or entropy increased or both???
thanx

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Postby MrMistery » Thu Mar 17, 2005 6:45 pm

First of all, i have no ideea of what angular momentum of electrons means! :roll: :roll:
Now, osmosis.I do not know much about this process from a biochemical point of view. But i do now that it is a passive process, so it shoul have nothing to do with energy or entropy. Water travels from the more diluated environment to the more concentrated one. It is probably o question of fluid dinamics
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Postby Jelanen » Thu Mar 17, 2005 8:25 pm

The process of osmosis happens due to an increase in entropy. If you have any sort of solution on one side of a osmotic membrane and pure water on the other, the water will move to the solution side (at least until the pressure pushing water through the membrane to the pure side is equal to the pressure of the water flowing through the membrane to the solution side due to osmosis). But taking pressure out of the equation, its only about entropy. Yet another thermodynamics question answered.
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increase

Postby 2810712 » Fri Mar 18, 2005 6:08 pm

Thank you Jelanen, but how can entropy increase here, i'm not getting that, my intution is exactly opposite , please help.

thanks.

_at_ MrMistry , sorry for that complecated eg. of angular momentum.
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IT HELPED

Postby 2810712 » Sat Mar 19, 2005 5:04 pm

THANK YOU !
revision of concepts provoked a series of thoughts and I think, now I've correct intutions regarding this.
Previously i thought that disappearance of conc. grad. and achievement of equal conc.s is a change from more non-standard state to a standard state , so this will
decrease the dis order.
Now, I got my answer from my post of 2nd law of thermodynamics - as more molecules on one side i.e. high conc. is similar to many naughty children in a class room , so they will try to go out and have a more specious condition. this will thus increase entropy.
I've given these all things becuase ,i wanted to check whether my intutions are really correct or not .also, it may help others to get this point cleared.

thanks

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Postby tavia » Thu Apr 07, 2005 2:21 am

HI GUYS
I HAEV BEEN READING THE DISCUSSION
I AM AFRAID TO ENTER AS I HAEV VERY LITTLE KNOWLEDGE ABOUT OSMOSIS AND DIFFUSION :oops:
AND I WOULD WANT OT ASK A QUESTION
WE SAY THAT FOR EVERY ACTION TO OCCUR ENERGY IS REQUIRED
THEN HOW COME OSMOSIS AND DIFFUSION IS PASSIVE?
NEED HELP
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Postby mith » Thu Apr 07, 2005 3:25 am

It uses stored energy as opposed to active transport which requires other energy sources. Imagine a ball falling from a high place, the falling is passive but the energy used to get it to the high place isn't obvious if you only see the falling ball.



P.S. The ball has air inside :D.
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Postby 2810712 » Thu Apr 07, 2005 7:21 am

See, the cell doesn't need to provide energy for osmosis and diffusion. So , its passive for cell. But , i think, each and every process needs energy , is some what confusing statement, as then one may think that every chem. reaction is endothermic.
So, the reaction may require some activation energy, but as a net effect it may release energy. Or may increase the disorder. Or both.

PS: NO. ball must have something else, atleast the ball used by some specefic people. :P

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Postby Poison » Thu Apr 07, 2005 4:30 pm

tavia wrote:WE SAY THAT FOR EVERY ACTION TO OCCUR ENERGY IS REQUIRED
THEN HOW COME OSMOSIS AND DIFFUSION IS PASSIVE?


take a glass of water and drop some ink in it. Dont shake the glass. wait and see how the ink diffuses. Now tell me. do you need energy for this?
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