At what presure will water vaporize at or close to freezing temperature?

Question

I ask thisquestion because I think there has never been liquid water on the surface of Mars.

Martian 'air pressure ' is about point 13 pound per square inch and Earths 'air pressure ' at sea level is 14 pounds per square inch.

I've read that the Martian 'air pressure' is equivalent to 100,000 feet up in Earths atmosphere.

There is no land on Earth that high so there is no possibility for a lake or stream but is it possible for liquid water like drops of water suspendend in the air to exists at that altitude.

OR back to the stated question :
At what air pressure will water vaporize at, close to or at freezing temperatures?



Where would a better place to post this be if this is not as good a place as I hope it will be.
I almost placed it in Chemestry , then I thought Earth Science , then Engineering, then Weather.
Then, since I was not sure , I placed it here in Other

Answer 1

At the freezing point, liquid water has a vapor pressure of 0.088 psi. The vapor pressure reaches 0.14 psi at 8 C (46 F).

I believe that the theory of liquid water on Mars in the past also assumes a higher atmospheric presure. At the least, I would expect the CO2 polar caps to be part of the old atmosphere.

Answer 2

According to one source, the vapor pressure of ice at 0 deg C is 681Pa = .0068atm or .088psi. If the surrounding atmospheric pressure is less than that, the ice will evaporate.

Answer 3

0.0 C has 4.5mm Hg vapor pressure
5 C has 6.6mm Hg
10 C has 9.2mm

from old chemistry text, also should be able to find this in Handbook of Chemistry and Physics

Answer 4

Who says that the atmosphere has ALWAYS been that way on Mars?