Predicting precipitates in a solution

AI Thread Summary
The discussion centers on predicting which precipitate will form in a supersaturated solution containing competing ions. Key considerations include the roles of thermodynamics and kinetics in determining long-term equilibrium products versus short-term reactions. Participants suggest that while electronegativity and ionic reactivity may influence outcomes, they may not adequately predict which precipitate is favored when a common ionic species is limited. The conversation emphasizes the importance of experimental validation, with suggestions to isolate variables and consider factors like temperature and molecular proximity. Ultimately, comparing solubility product constants (Ksp) is highlighted as a reliable method to determine the stable precipitate in equilibrium, distinguishing between the formation process and the final stable state.
Baho Ilok
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Let's say we have a solution supersaturated with several species of ions, and there are a few potential precipitates predicted to be formed that all have one contain one species in common (therefore they are competing for that common ionic species). How can we predict which species will precipitate, assuming that the common species is not in excess?
 
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Electronegativity difference perhaps? Sakto ba? Pagtawas oi.?:)

This is a topic on chemical kinetics. Rate of reaction.
 
Riverbirdy said:
Electronegativity difference perhaps? Sakto ba? Pagtawas oi.?:)

This is a topic on chemical kinetics. Rate of reaction.
I can't afford it :cry:

Well I was thinking maybe this may be more related to the thermodynamic properties of the predicted precipitates or their formation. Although electronegativity might play a role, I worry that an analysis through that framework might get too complicated since it is in the atomic scale.

As for a reaction kinetics approach, I worry it might not provide us information on which precipitate is favored to form.
 
Baho Ilok said:
As for a reaction kinetics approach, I worry it might not provide us information on which precipitate is favored to form.

May be isolating one over the other specie (1 to 1) might help you somehow to analyse the problem at a fixed temperature. Does temperature change during the mixing of constituents?

I don't know, if its an experiment your doing, you have no worries at all. As nature dictates what's going to happen. If you are may be verifying or proving a theory in reality, I think it needs a lot to think. Observation wins over set of theories.
 
Thermodynamics would tell you what to expect in a long term, kinetics will predict short term outcome - and they don't have to be identical.

These things are best checked experimentally.
 
Riverbirdy said:
May be isolating one over the other specie (1 to 1) might help you somehow to analyse the problem at a fixed temperature. Does temperature change during the mixing of constituents?

I don't know, if its an experiment your doing, you have no worries at all. As nature dictates what's going to happen. If you are may be verifying or proving a theory in reality, I think it needs a lot to think. Observation wins over set of theories.
It's all theoretical.
 
Borek said:
Thermodynamics would tell you what to expect in a long term, kinetics will predict short term outcome - and they don't have to be identical.

These things are best checked experimentally.
This is a mere theoretical analysis, actually.

Basically, the idea is that if I had a solution supersaturated with ions A, B, X, and a variety of other ions; both AX and BX are known to be stable salts, but X is not available in excess, which of the two would be favored to precipitate after the solution reaches equilibrium (long term)? I initially thought that reactivity of the ionic species would dictate which would precipitate, but I read that it only works for single displacement reactions. And for this case, I believe it is a more complex system (or is it?).

I would appreciate if somebody could assist me with this analysis. Thank you!
 
Baho Ilok said:
This is a mere theoretical analysis, actually.

Basically, the idea is that if I had a solution supersaturated with ions A, B, X, and a variety of other ions; both AX and BX are known to be stable salts, but X is not available in excess, which of the two would be favored to precipitate after the solution reaches equilibrium (long term)? I initially thought that reactivity of the ionic species would dictate which would precipitate, but I read that it only works for single displacement reactions. And for this case, I believe it is a more complex system (or is it?).

I would appreciate if somebody could assist me with this analysis. Thank you!
It would somehow end up to proximity of molecules and foremost opposite ions. Just a mere guess.
 
Riverbirdy said:
It's would somehow end up to proximity of molecules and foremost opposite ions. Just a mere guess.
I believe that would only apply to predicting "short-term" (or instantaneous, even!) products. I am concerned with the equilibrium products (long term), which I assume that all species were allowed to "meet with each other" and eventually "find their best partner," so to speak.

Nonetheless, I thank you for your input. I appreciate it.
 
  • #10
Baho Ilok said:
I believe that would only apply to predicting "short-term" (or instantaneous, even!) products. I am concerned with the equilibrium products (long term), which I assume that all species were allowed to "meet with each other" and eventually "find their best partner," so to speak.

Nonetheless, I thank you for your input. I appreciate it.
If it has to be long term, then it's a factor of gravity, heavy molecules settles lighter ones float.:cry: mao ba kabs?
 
  • #11
Riverbirdy said:
If it has to be long term, then it's a factor of gravity, heavy molecules settles lighter ones float.:cry: mao ba kabs?
Na hala, sige kabs puwede na ni. Pasar na lagi ka :wink:
 
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  • #12
Baho Ilok said:
Na hala, sige kabs puwede na ni. Pasar na lagi ka :wink:
So nice to find you here:smile:.-msu-iit
 
  • #13
Baho Ilok said:
which of the two would be favored to precipitate after the solution reaches equilibrium (long term)?

You are not asking about which one will precipitate, but about which one is the stable, final form, these are slightly different things.

For that comparing Ksp should be perfectly enough (as it stems from thermodynamics).
 
  • #14
Borek said:
You are not asking about which one will precipitate, but about which one is the stable, final form, these are slightly different things.

For that comparing Ksp should be perfectly enough (as it stems from thermodynamics).
I see, thank you for the correction. I will take a look at the problem considering Ksp. This definitely makes sense. Thank you, I really appreciate your help!

Have a good day!
 
  • #15
Riverbirdy said:
So nice to find you here:smile:.-msu-iit
:smile:
 
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