solubility of gases

[madiha]

What makes a gas to be lesser soluble in warm/hot water than in colder one?

[elementcollector1]

What makes a gas to be lesser soluble in warm/hot water than in colder one?

 

If I had to guess, it would probably be because at higher temperatures, the gas molecules are bouncing around more rapidly and thus more able to leave solution due to their energy.

Anyone else?

[Ophiolite]

I confirm elementcollector1's intuition. Higher temperatures mean molecules with higher kinetic energy and therefore more molecules likely to leave solution.

[mississippichem]

A good approximation for the solubility of gases in liquids is found in Henry's Law:

 

[math] p_{\chi}=k(T)c [/math]

 

Where [math] p_{\chi} [/math] is the partial pressure of the gas above the liquid, c is the concentration of the gas in the liquid and k(T) is the temperature dependent Henry's Law coefficient. The Henry's Law coefficient is best found experimentally but is roughly proportional to [math] e^{1/T} [/math].

 

I think the intuition given above is a valid way to think about it. Keep in mind that heuristics can get you into trouble in physical chemistry though if you're not careful. Case in point, if you have a gas that has a different chemical identity in solution than it does in the gas phase (think CO₂ and carbonic acid) then all of this is moot.