In reply to Grimer's message of Tue, 09 May 2006 18:55:39 +0100: Hi Frank, [snip] >There was one thing that occurred to me though. >Imagine that water is a ball bearing type gas at >STP. One gram-molecule will occupy a bit less >than 22 litres. > >Let's say one gram mass occupies 1024 cc to make >the maths easy. > >At 2 atmospheres we have 512 cc. > 4 " " " 256 " > 8 " " " 128 " > 16 " " " 64 " > 32 " " " 32 " > 64 " " " 16 " > 128 " " " 8 " > 256 " " " 4 " > 512 " " " 2 " >1024 " " " 1 " > >Now 1000 atmospheres isn't 3750 atmospheres >admittedly - but its the right order of magnitude, >and at STP water isn't a gas but a vapour and >presumably has quite a bit of Beta-atmosphere >pressure on it already. > >In effect this shows how the "attractive" forces >which supposedly hold liquid water together can >be seen as negations of the external Beta- >atmosphere pressure. No doubt the argument could >be refined by working at CPT (Critical Pressure >and Temperature) rather than STP. [snip] The latent heat of evaporation is the additional heat that needs to be added to water to overcome the "attractive" forces between the molecules, as opposed to simply raising the temperature, i.e. increasing the kinetic energy of the molecules. At the boiling point of water (at 1 atm) this is 539.8 cal/gm. If this is multiplied by the density of water i.e. 1 gm/mL then the result is energy/volume = pressure. That pressure is 22300 atm. Regards,
Robin van Spaandonk http://users.bigpond.net.au/rvanspaa/ Competition provides the motivation, Cooperation provides the means.
