Impossible to centrifuge salt out of water?

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SUMMARY

The discussion centers on the feasibility of centrifuging salt out of water, specifically addressing the behavior of dissolved salt ions in an aqueous solution. It is established that while salt does not precipitate out like non-ionizing substances, the concept of exceeding the solubility limit through centrifugation is explored. The interaction between water molecules and salt ions, where positive and negative ions associate with polar water molecules, suggests that centrifugation could potentially lead to a concentration of ions at the bottom of the centrifuge. However, the consensus indicates that practical centrifugation of salt from water is not achievable under normal conditions.

PREREQUISITES
  • Understanding of solubility principles and saturation limits
  • Knowledge of ionic dissociation in aqueous solutions
  • Familiarity with centrifugation techniques and their applications
  • Basic chemistry concepts related to polar molecules and ion interactions
NEXT STEPS
  • Research the solubility product constant (Ksp) for various salts
  • Learn about the principles of centrifugation and its effectiveness in separating mixtures
  • Explore the concept of precipitation reactions in chemistry
  • Investigate the behavior of ions in polar solvents, focusing on hydration shells
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Chemistry students, laboratory technicians, and anyone interested in the separation of ionic compounds from solutions.

wasteofo2
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I've been told (by my high school chemistry teacher, which obviously means it isn't necessarily true), that when salt dissolves in water, that you cannot centrifuge it out.

I understand that you can't centrifuge it out like you would sugar, or something that doesn't ionize, but it seems to me that you should be able to centrifuge it out.

Water can only accept a concentration of so many salt ions per so many water molecules, and once that acceptable concentration is exceeded, salt will precipitate out of solution, correct?

Furthermore, when salts dissolve in water, and the ions dissociate, the positive ions will tend to stick near the - end of water, and the negative ions will be attracted to the positive end of water. So, if you're dealing with an unsaturated solution, you have some water molecules that essentially have ions loosely bonded to them, making them heavier.

In that the water molecules that have ions attracted to them are heavier, it seems that if you centrifuge water, these molecules will go to the bottom of the centrifuge tube.

If you were to use enough force, it should seem that you'd get enough of the water with ions attracted to it to go to the bottom that you might actually surpass the molarity of ions that water can take, and that some salt would actually previpitate out.

Even if you couldn't get the proper ratio of ions to water molecules for salt to precipitate out, it seems that the ionic sides of the water should be sent furthest down, since the ions of any salt are heavier than water's components.

Is my logic correct?
 
Last edited:
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That's a good point. I am curious to know the answer, too.
 

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