h2o o2 energy

[meni ohana]

hello, my question is how come molecule of water, although much lighter than molecule of oxygen, needs much more enegrgy to become a gas and mix in the air? is it the way energy spread or absorbd in the molecule? thank you

[Ygggdrasil]

A liquid consists of a collection of many molecules that are losely bound through non-covalent intermolecular bonds. A gas is a collection of many non-interacting molecules. Therefore, going from a liquid to a gas involves breaking those non-covalent bonds between molecules, and the energy required to vaporize a compound is related to the energy of these intermolecular bonds.

Molecular oxygen is a non-polar molecule that interacts with other molecules of oxygen through very weak London dispersion forces (http://en.wikipedia.org/wiki/London_dispersion_force#London_dispersion_force). Water molecules, on the other hand, are polar and can interact with other water through hydrogen bonds, a very strong type of intermolecular bond.

Although it is true in general that more massive molecules will have higher boiling points, it has nothing to do with the molecule's weight. Rather, larger molecules will experience larger dispersion forces that keep the molecules together.