[jamessmart]

"In water a small amount of silver chloride dissolves to produce an equal number of silver and chloride ions. Over time an equilibrium is established in which the amount of silver chloride dissolving from the solid phase is balanced by exactly the same amount precipitating. When this point is reached the solution is said to be saturated with respect to silver chloride."
is the amount of silver chloride dissolving from the solid phase is balanced by exactly the same amount precipitating? could you please give an example values please so i understand the number of moles precipitating and dissolving involved?

and majorly a saturated solution is when the solution has dissolved the maximum amount of solute
but in the example above how how there are some solids (NaCl (s)) formed? and why is there an equilibrium established- why don't all the ions in NaCl dissociate completely when they dissolve in water?

thank you

[UG]

"In water a small amount of silver chloride dissolves to produce an equal number of silver and chloride ions. Over time an equilibrium is established in which the amount of silver chloride dissolving from the solid phase is balanced by exactly the same amount precipitating. When this point is reached the solution is said to be saturated with respect to silver chloride."

is the amount of silver chloride dissolving from the solid phase is balanced by exactly the same amount precipitating? could you please give an example values please so i understand the number of moles precipitating and dissolving involved?

Sorry, don't quite see what you are getting at with the underlined part. Yes, the amount of solid forming is balanced exactly by the amount of solid dissolving

and majorly a saturated solution is when the solution has dissolved the maximum amount of solute but in the example above how how there are some solids (NaCl (s)) formed? and why is there an equilibrium established- why don't all the ions in NaCl dissociate completely when they dissolve in water?

Where did the sodium chloride come from? I thought we were talking about silver chloride?

[jamessmart]

sorry
if you dissolve the solute in a solution until you cannot dissolve more, how can you tell? and would there be any solids formed?
i got confused because the books say that even if you reach saturation point of a solution, then there will be an equilibrium such as AgCl(s) --><-- Ag(aq) + Cl-(aq)
why? i thought AgCl(s) dissolved completely even if you reach saturation point.

thank you

[UG]

if you dissolve the solute in a solution until you cannot dissolve more, how can you tell? and would there be any solids formed?
i got confused because the books say that even if you reach saturation point of a solution, then there will be an equilibrium such as AgCl(s) --><-- Ag(aq) + Cl-(aq)
why? i thought AgCl(s) dissolved completely even if you reach saturation point.

Have you ever tried putting in lots and lots of table salt into a cup of water? At the start, it seems no matter how much you throw in, it just keeps dissolving, but eventually you put in another grain of salt and it doesn't dissolve any more, it'll just stay there. At this point your solution is saturated. At this point there will be an equilibrium between solid NaCl and the ions in solution. On the surface of that grain of salt you are going to have sodium and chloride ions entering the solution but at the same time an equal amount of sodium and chloride ions are precipitating out of the solution and forming solid NaCl on your grain of salt. Just remember that equilibrium is dynamic, it is not static, ie, the atoms and ions don't just stop when they're at equilibrium.
Maybe this was helpful.

[jamessmart]

but why do you getting solids forming if you have dissolve the solids in the solution even at saturation- hasn't the solids dissociated in the solution?
do you get an equilibrium only when the solution is saturated?

[UG]

If I didn't put in that last grain of salt then the solution would be saturated and there is no solid. But even a slight decrease in volume will cause solid to precipitate out and increasing the volume will mean it is unsaturated again. Most of the time, there is just going to be a lump of some solid in the solution and some of it will dissolve to form a saturated solution.

[Borek]

You may always decant saturated solution end have it without any solid - but small change on temperature (usually, but not always, lowering the temp) will precipitate some of the solid out.

[jamessmart]

when and why do you have an equilibrium?
solids forming to ions and ions forming solids? why?