Could someone explain to me why the solubility of any gas in water decreases with rising temperature? (Yes, it is a homework question, but rather than copy straight out of the book or Google the answer and copy I'd like to try to understand the answer.) Thanks!

Question

anonymous · Answer

Is it a result of a drop in pressure?

ganeshie8 · Answer

hmm nice, fascinated by chemistry ha !

preetha · Answer

Think about it this way.  When a gas dissolves in water, the gas molecules are held by intermolecular forces of attraction.  When you increase the temperature, the gas molecules mover faster and have greater energy.  So they are able to overcome the forces of attraction and escape.  This leads to a lower solubility.

anonymous · Answer

Thank you. That helps quite a bit actually. Similar to what my book was saying, but you explained it in a much simpler fashion. Does pressure have anything to do with it at all then?

preetha · Answer

Well solubility of a gas in water will increase as the pressure increases.  Same logic. Pressure brings molecules closer together.  keeps them together.  That is why a coke can has CO2 dissolved in it and is fizzy.  Contents are under pressure.  If you release the pressure, coke goes flat.  No dissolved CO2

anonymous · Answer

Alas, clarity. Thanks again!