Predicting precipitates in a solution

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Discussion Overview

The discussion revolves around predicting which precipitate will form in a supersaturated solution containing multiple ionic species, particularly focusing on the competition for a common ionic species. Participants explore concepts related to chemical kinetics, thermodynamics, and the conditions affecting precipitate formation.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants suggest that electronegativity differences might play a role in predicting precipitate formation, though concerns about complexity at the atomic scale are raised.
  • There is a discussion on the relevance of thermodynamic properties versus kinetic factors, with some arguing that thermodynamics provides long-term expectations while kinetics addresses short-term outcomes.
  • One participant proposes isolating ionic species to analyze the problem at a fixed temperature, questioning whether temperature changes during mixing might affect results.
  • Another participant emphasizes that the analysis is theoretical and asks for assistance in determining which precipitate would be favored after reaching equilibrium, given the presence of stable salts AX and BX.
  • Concerns are raised about the applicability of reactivity rules, which may only apply to single displacement reactions, suggesting that the system may be more complex.
  • There is a mention of the role of molecular proximity and the settling of heavier molecules in the context of long-term equilibrium products.
  • One participant corrects another, clarifying that the inquiry is about stable final forms rather than which precipitate will form first, suggesting that comparing solubility products (Ksp) could be sufficient for analysis.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the factors influencing precipitate formation, including the roles of thermodynamics, kinetics, and molecular interactions. The discussion remains unresolved with no consensus on a definitive approach or conclusion.

Contextual Notes

Participants note that the analysis is theoretical, and there are concerns about the complexity of the system and the assumptions made regarding ionic interactions and conditions affecting precipitate formation.

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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