Samantha J.

asked • 10/01/12

Why does salt crystals dissolve in the water?

why does salt crystals dissolve in water?

6 Answers By Expert Tutors


Robert C. answered • 10/01/12

5.0 (44)

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Stanton D.

Whoops, Robert C., enthalpy is H and entropy is S. Also, it's a "sea" of H2O, not a "see"!
Otherwise, a nice explanation. I particularly liked the way you related entropy and number of ion position states.


Robert C.

Yes, that is what I said in my post. I quote myself:
"ΔG is the change in free energy. If ΔG < 0, the process is spontaneous. ΔH is the change in enthalpy, T is the absolute temperature, and ΔS is the change in entropy." (emphasis added)
I am unsure if you intend your comments as a correction of my answer, but that is how it came across. Please explain what part you think is incorrect.


Cecelia G.

No need to get defensive!
Here is the part I think Stanton is referring to (from the second paragraph):
"Free energy can take the form of bonds (enthalpy, S) or degree of disorder (entropy, H)."
Thanks for the detailed explanation, though. It really helped!


Natalee L. answered • 10/01/12

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Master's in Biological Science

Dick B.

I would like to emphasize the part where Natalee states that "the attraction between the water and the ions overcomes the attraction the ions have for one another." This is why ionic compounds like NaCl are soluble, but BaSO4 is not. Sodium and chloride ions are both singly charged (+1 & -1), while barium and sulfate ions are doubly charged (+2 & -2). The higher the charge, the stronger the attraction between ions. Other things can affect the solubility, too. Crystal structure is one. The amount of covalent character is another. Silver chloride, for example, involves singly charged ions, but has a good deal of covalent character, which decreases its solubility.


David R. answered • 10/22/12

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Robert C.

That is a good point, David.



Param S. answered • 03/22/21

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Thomas C. answered • 04/03/20

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Chinenye G. answered • 10/31/20

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