Why Can't Salt Be Separated from Water Using a Centrifuge or by Letting It Sit?

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Discussion Overview

The discussion centers on the feasibility of separating salt from water using a centrifuge or by allowing the mixture to sit. Participants explore the nature of saltwater as a homogeneous mixture and the interactions between salt (NaCl) and water, examining the implications for separation methods.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant states that saltwater is a homogeneous mixture, implying that the components are not chemically bonded and questioning why denser NaCl does not sink in water.
  • Another participant clarifies that NaCl exists as dissociated ions rather than molecules, suggesting that the concept of density may not apply in the same way for individual ions.
  • This participant also notes that molecular collisions due to thermal motion are significantly more impactful than gravitational effects, which may hinder separation methods.
  • A different participant emphasizes that the dissolution of NaCl in water is due to low electrostatic forces and that the solution cannot be separated through methods like filtration or centrifugation.

Areas of Agreement / Disagreement

Participants generally agree on the nature of saltwater as a homogeneous solution and the challenges of separation, but there are differing views on the implications of density and the effectiveness of various separation methods.

Contextual Notes

Participants mention the effects of thermal motion and the nature of ionic dissociation, but do not fully resolve how these factors interact with gravitational forces in the context of separation techniques.

tony873004
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Why can’t I separate salt from water with a centrifuge, or simply by letting it sit for some time? Salt water is a homogeneous mixture, not a compound. So the salt and the water are not chemically bonded. Why don’t the denser NaCl molecules sink to the bottom of the H20 molecules?
 
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NaCl are not in form of molecules, they are dissociated (not that it answers your question).

Notion of density doesn't make much sense for a single molecule. Even if it was making sense, effects of molecular collisions (due to thermal motion of molecules) are orders of magnitude higher that effects of gravity.
 
Thanks Borek!
 
Salt and water are homogeneous solutions , yes and NaCl can easily dissolve in water because of its low electrostatic single bond force .

Water easily dissolves it . It is a true solution cannot be seen , cannot be collected through permeable membrane or filter paper .

No matter of centrifugal force , it cannot be separated .
 

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