Why do gases become more soluble at lower temperatures?

[lald6103]

Hello

I recently read that the antarctic crocodile icefish (Channichthyidae) has colourless blood because it lacks haemoglobin. Apparently it can transport large amounts of oxygen around the blood in dissolved form because of its low body temperature (-1.8 to 2 degrees C).

I was just after an explanation of this? What law(s) of physics state(s) that a gas is more soluble at lower temperatures?

Regards

Louis

 

[Bystander]

Generally speaking entropy is at work; lower T favors condensation of gases.

 

[nasu]

It's not a general rule.
Some gases are more soluble in some solvents at lower temperatures.
An example is oxygen dissolved in water.

It's a case by case thing. Similar to some chemical reactions release energy (exothermic) and others need energy from environment (endothermic).
The solubility case depends also on what happens when the gas dissolves: heat released or absorbed.

 

[jim mcnamara]

Solubility of oxygen in water at varying temperatures and pressures: http://water.usgs.gov/owq/FieldManual/Chapter6/table6.2_6.pdf
All other things ignored, the amount of oxygen that can dissolve in water increases as water temperature goes down - bystander said succintly.

 

[Bystander]

He solubility in water is the only exception of which I'm aware, and that's only through a limited T range.

 

[nasu]

Water is not the only solvent.
The solubility on oxygen in alcohol increases with temperature.
So a "general" explanation like lower temperature favors condensation of gases is missing something.