On 9 mai, 15:54, lugoteehalt <lugoteeh...@[EMAIL PROTECTED]
> wrote:
> On 9 May, 13:40, Crown-Horned Snorkack <chornedsnork...@[EMAIL PROTECTED]
>
> wrote:
>
> > Suppose that you have a really deep body of fresh water - which has
> > actual temperature of 3,98 Celsius near surface, below a thin layer of
> > surface ice and a thin layer of water colder than 3,98 degrees.
>
> > As water is lowered from the surface, its density increases
> > (compression). But adiabatic compression should cause some increase of
> > actual temperature, even in liquids and solids.
>
> > The melting point decreases up to about 2200 atmospheres (ice Ic),
> > then begins to rise. Ice VI forms at about 6000 atmospheres, and
> > actual temperature of about 0,16 Celsius. It is denser than water, and
> > naturally its freezing point increases with pressure.
>
> > At which temperature and pressure would ice VI come to equilibrium
> > with fresh water adiabatically compressed from 0 atm 3,98 Celsius?
>
> "and naturally its freezing point increases with pressure." Hope I'm
> not being dense, little pun, but could you explain this assertion?
> Are you absolultely certain it is true?
Yes, absolutely.
The freezing/melting point of ice Ic decreases with pressure because
water is denser than ice (and water has latent heat of freezing - heat
is released when water freezes). All substances which expand on
melting have melting point that increases with pressure, and this
includes high-pressure ices. (The exception is helium 3, whose melting
point decreases with pressure because, although it expands on melting,
it also releases heat on melting).
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