On Monday, 5 March 2018 16:07:26 UTC+11, James McGinn wrote:
> On Sunday, March 4, 2018 at 7:32:10 PM UTC-8, Arindam Banerjee wrote:
>
> > > If you were to go to outer space, where the pressure is zero, causing the
> > > H2O to boil at room temperature,
> >
> > How can a single molecule of water "boil" anywhere? Boiling is a phenomenon involving a lot of water subjected to external heat.
>
>
>
> >
> > and then you were to vent it out into outer
> > > space you might be successful in causing H2O molecules to remain singular.
> >
> > I would say, that in outer space with no other molecules around to
> > push H2O molecules apart, the tendency for them to stick to form
> > ice would be more pronounced than on the Earth's surface.
>
> At room temperature and zero pressure they would be above boiling
> temperature and would fly apart, and they would have nothing to stick to in
> outer space.
I don't understand the concept of room temperature and zero pressure.
When pressure is zero (as in outer space) the temperature is zero so far as the ambient is concerned given no sunlight, etc.
So how exactly can one have room temperature and zero pressure on Earth?
Taking out the air from a cavity thus reducing the pressure to say zero reduces the temperature of the cavity where the air existed.
P1V1/T1 = constant as per universal gas law
Making P1 tending to 0, keeping V1=V2, means T1 tending to 0 to maintain the gas law.
The room temperature is measured outside the cavity.
> But all of this is academic. The point is that the isolation you postulated
> doesn't take place under normal conditions.
All I am saying is that when a molecule of water evaporates, what does happen?
Must two or more molecules of water simultaneously evaporate and unite automatically to form a nanodroplet of water - and this, always?
or
Does a single molecule of water evaporate at room temperature and remain single until it finds another molecule or nanodroplet to unite with?
I fully agree with you that under 100degC at NTP water has no business to remain as a gas - it has to be water. However, what happens in a closed space, as in the petrol can experiment I had talked about, is not what happens in an open space.
>
> > > But here on earth, under normal atmospheric pressures at the surface and an
> > > atmosphere that is saturated with H2O, even in the driest of dry
> > > environments, that would be impossible.
> >
> > Dry air by definition has no H2O,
>
> You are being picky for no good reason. Dry air in the troposphere is never 100% dry. And it would not be able to remain hot in the proximity of other air molecules. I suppose, possibly, at the top of the troposphere where it really is dry and somewhat hot an H2O molecule might be able to remain monomolecular. But that is academic.
I am not an academic. I am a practical engineer. I would say that simulation of a very small space tracking the behaviour of each and every molecule in it (coming and going from the space, and uniting or repelling therein) would give a fair clue about the way water molecules behave in air. You can have your nanodroplets there, or a mixture of nanodroplets and individual molecules.
This simulation approach, I found very useful to model complex call centre networks. The recommndations made as a result had a lot of backing from the most fundamental positions.
So this simulation, if made good enough, will provide proper predictions with respect to humidity.
With further improvements, it could lead to developments relating to cloud seeding, creation of rain, etc. and that would be a great boon for dry countries.
>
> so a single molecule of H2O will find no other molecule of H2O with which to stick. If there are other molecules then sticking to form multimolecules will become a random issue involving the chances of collision. I just don't get the impossibility part, unless you are holding that as soon as 100degC steam is released into dry air, all the monomolecules MUST unite to form multimolecules. ALL of them.
>
> Yes, they reform into multimolecules almost instantly, just as soon as they cool below 100C.
If you say so. I would like your assertion to be based upon simulation as I described above. How the 100deg water molecules would move (faster than say at 10deg) and what chaces they have of uniting in a volume where they are released.
Actual experiments to show all the steam uniting to form nanodroplets, with nothing left monomolecular, that would be wonderful.
>
> >
> > I find this hard to believe, for steam say at 1000degC when released into dry air of the Earth, with no containment, will push out with much greater force, and expand in all directions, while cooling. When expanding out at greater than 100degC, they will still remain monomolecules pushing out. At some stage these monomolecules must get far too isolated to ever unite.
>
> Not possible. Singular H2O molecules reattach to each other just as soon as they cool. And they cool instantly as they reenter the atmosphere.
>
> > > There is one thing about H2O molecules that would be extremely difficult for
> > > me to explain to you. So I won't even try.
> >
> > Okay. It does look like a cop-out, though.
>
> I'm going to release something in about 2 weeks that will fully inform you. Try not to step in front of a bus until then.
>
> >
> > But what it amounts to is that
> > > the characteristics of H2O individually are extremely different from their
> > > characteristics collectively.
> >
> > You are not making yourself clear. What do you mean by "characteristics of H2O individually"? Do you mean that monomolecular water has extremely different characteristics than multimolecular water? If so, who disputes that?
>
> Who doesn't.
>
> >
> >
> > > Individually H2O molecules are extremely
> > > polar. And thus, they are extremely attracted to each other.
> >
> > Okay.
> >
> >
> > And it is not
> > > until they are hydrogen bonded to other water molecules that they lose this
> > > polarity. In other words, H2O polarity is neutralized by hydrogen bonds.
> >
> >
> > Who does not know that?
>
> Now you just seem confused.
>
> Of course H2O molecules bond to each other to form clouds, mists, fog, dew, rain, etc.
>
> I just said they were neutralized. You aren't following.
>
> >
> > I would say, this behaviour is much like plastic cups cupping each other to form a single group entity.
>
> I have a more technical explanation that has to do with symmetry and stretched electron clouds. Give me 2 weeks.
>
> >
> > The point is that individual molecules can only unite if they find each other to do so. Until they can, they must move in whatever temperatures singly.
>
> That's not my point that's your point. Good luck proving it.
>
> >
> > In graphic terms, this means plastic cups moving in air, till they find another in the right position to cup into. But other stuff like bigger plates, ie oxygen and nitrogen molecules, are also there - and these plates push the cups away till they come to a situation when they all cup together to form a big cuppy entity like cloud, mist, etc.
>
> Why would you expect me to take this kind of off-hand speculation seriously?
>
> >
> > > I am one of a handful of people that understand what I explained to you in
> > > the above paragraph (and the other four learned it from me).
> >
> > We all need to learn from each other.
>
> Be patient. And always use the crosswalk.
>
> > >
> > > In order for an H2O molecule to remain singular under any normal atmospheric
> > > conditions it would have to remain very hot, and that means it would be
> > > moving very fast and, somehow, avoid crashing into other molecules in the
> > > atmosphere and it would have to stay away from any other water molecules.
> > >
> > > And so, for both of these reasons, steam will not persist form much time in
> > > earth's atmosphere.
> > >
> > > Microdroplets and nanodroplets, however, are a different story. The H2O
> > > molecules in a nanodroplet maintain many hydrogen bonds and, therefore, they
> > > are highly neutralized.
> > >
> > > Nanodroplets can maintain separation from other H2O nanodroplets because
> > > they are not all that attracted to each other--in fact their outer shell of
> > > "surface tension" is hydrophobic, meaning they will repel each other.
> > >
> > > H2O is not just poorly understood it has been badly mischaracterized by the
> > > fact that us humans want to believe it is something it is not--simple.
> > >