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I found this quote on a Chemistry LibreTexts website:

If the heat given off in the dissolving process is greater than the heat required to break apart the solid, the net dissolving reaction is exothermic (energy given off). The addition of more heat (increases temperature) inhibits the dissolving reaction since excess heat is already being produced by the reaction. This situation is not very common where an increase in temperature produces a decrease in solubility.

I understand that when dissolving releases more energy than is being used in the dissolution, the net reaction is exothermic. Why exactly does the excess heat inhibit the dissolution? I cannot see the reason why. Could somebody explain this in more detail?

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  • $\begingroup$ On which website? Gah, ninja'd. Also citation is about solids. Dissolving gas decreases entropy, so with rise in temperature, process becomes less favorable. $\endgroup$ – Mithoron Dec 30 '18 at 23:25
  • $\begingroup$ Water, for example, holds the most dissolved gas just above freezing... but in the transition to ice, most gases are excluded (methane being an exception), leading to bubbles in the ice. Boiling the water before freezing it removes dissolved gases, enabling formation of bubble-free ice. $\endgroup$ – DrMoishe Pippik Dec 31 '18 at 0:32

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