How fast on average are H2O molecules zipping around/ricocheting in boiling water?

Factual Questions
1

See query. Thinking about kinetic energy recently, and wanted to ease my way into it, so to speak.

2

1,500 miles per hour (!)

http://www.verticallearning.org/curriculum/science/gr7/student/unit01/page05.html

3

I’m not sure how well Maxwell-Boltzmann applies to molecules with strong, long-range interactions like water. But I’m also not sure how well it doesn’t.

4

Yeah, if liquid water molecules are moving that fast on average, it’s not particularly meaningful because the mean free path in a liquid is negligible.

If you want a demonstration of how fast chemical reactions can occur in water, get yourself a greasy pan and drop a bit of soap into it. The visual change moves much faster than one expects, though not at the absurd speed that the particles might be nominally moving at. At least, it does whenever I do the dishes - it’s far faster than the bubbles of water bobbing on the surface.

5

This guy suggests using the self-diffusion coefficient of water, and arrives at an order of magnitude of about 10 m/s

6

I think they ought to have kinetic energy similar to air molecules, which move at a bit over the speed of sound. In fact, the speed of air molecules is the main factor that sets how fast sound propagates. They should have the same energy because “boiling point” basically means they’re moving fast enough to move like air molecules.

To have the same kinetic energy they’d be moving faster than air molecules because they’re almost two times less massive.

So I think the 1500 mph value is plausible.

I didn’t look anything up, however, I’m just reasoning it out.

7

Just posted another thread on liquid phase, while I think about this one. I, for one, will consider the two queries as a pair.

Thanks to all…