- #1
PPonte
Why does the solubility of KNO3, in water, rises with increasing temperature and the solubility of Na2SO4 descreases? 
Thank you.
Thank you.
Understanding Solubility: KNO3 and Na2SO4 in Water
- Thread starter PPonte
- Start date
-
- Tags
- Solubility
Click For Summary
Discussion Overview
The discussion centers on the solubility behavior of KNO3 and Na2SO4 in water, specifically addressing how temperature affects their solubility. Participants explore the thermodynamic principles underlying these phenomena.
Discussion Character
- Technical explanation
- Conceptual clarification
- Debate/contested
Main Points Raised
- One participant notes that the solubility of KNO3 increases with temperature, while the solubility of Na2SO4 decreases.
- Another participant explains the dissolution process involves two phases: the endoenergetic separation of ions and the exoenergetic solvation (hydration) process.
- The same participant proposes that if the energy required to separate ions is greater than the energy released during solvation, the dissolution is endoenergetic, and vice versa for exoenergetic processes.
- The participant concludes that KNO3 is globally endoenergetic and thus its solubility increases with temperature, while Na2SO4 is globally exoenergetic, leading to decreased solubility with rising temperature.
- Another participant expresses agreement with the explanation provided regarding the dissolution processes.
Areas of Agreement / Disagreement
While there is agreement on the thermodynamic principles discussed, the overall implications regarding the solubility trends of KNO3 and Na2SO4 remain open for further exploration, as no consensus is reached on the correctness of the conclusions drawn.
Contextual Notes
The discussion does not clarify specific conditions under which the solubility behaviors are observed, nor does it address potential exceptions or additional factors influencing solubility.
- #2
Gokul43201
Staff Emeritus
Science Advisor
Gold Member
- 7,213
- 25
What are your thoughts ?
We can't help you unless you help yourself.
We can't help you unless you help yourself.
- #3
PPonte
I am sorry. I usually help people who do not present their thoughts, I never remeber those rules.
Here are my thoughts:
1. The dissolution of a salt involves two phases. First, the separation of the ions, which is endoenergetic because involves breaking of ionic bonds and, second, the solvatation, in this case, an hydration since the solvent is water, which is exoenergetic.
2. If the energy consumed in the first phase is greater than the energy freed in the second phase, the dissolution of the salt is globally endoenergetic. If the energy consumed in the first phase is minor than the energy freed in the second phase, the dissolution of the salt is globally exoenergetic.
Conclusion: I think, then, that the dissolution of KNO3 is globally endoenergetic, so rises with increasing temperature, and the dissolution of Na2SO4 is globally exoenergetic so decreases with increasing temperature.
Am I right?
Here are my thoughts:
1. The dissolution of a salt involves two phases. First, the separation of the ions, which is endoenergetic because involves breaking of ionic bonds and, second, the solvatation, in this case, an hydration since the solvent is water, which is exoenergetic.
2. If the energy consumed in the first phase is greater than the energy freed in the second phase, the dissolution of the salt is globally endoenergetic. If the energy consumed in the first phase is minor than the energy freed in the second phase, the dissolution of the salt is globally exoenergetic.
Conclusion: I think, then, that the dissolution of KNO3 is globally endoenergetic, so rises with increasing temperature, and the dissolution of Na2SO4 is globally exoenergetic so decreases with increasing temperature.
Am I right?
- #4
Gokul43201
Staff Emeritus
Science Advisor
Gold Member
- 7,213
- 25
Perfectly.
PS : Please do not help folks that show no original effort. It is rarely helpful to the student in the long run.
PS : Please do not help folks that show no original effort. It is rarely helpful to the student in the long run.