Re: Continuations

Michael S <already5chosen@yahoo.com> schrieb:

On Thu, 18 Jul 2024 18:48:45 -0000 (UTC)
Thomas Koenig <tkoenig@netcologne.de> wrote:
>

Michael S <already5chosen@yahoo.com> schrieb:

On Thu, 18 Jul 2024 17:06:52 -0000 (UTC)
Thomas Koenig <tkoenig@netcologne.de> wrote: 

It does work far away from the equilibrium (which is the point). 

>
But how far?
Does it work for EA/RT outside of, say [-10:+12] ? 

 
Ea is almost always positive; if if was negative, it would mean that
a reaction is is slowed down by increasing temperature (and by this
don't mean the reverse reaction).

>
In the branch of physical chemistry that I was taught before switching
to completely different profession, that's not that rare.
For example, when temperature grows from 1500 degrees toward 1550
the transfer of phosphorus from molten steel to slag decelerates
greatly.

Do you happen to recall if that process was limited by thermodynamic
equilibrium, by mass transfer or indeed by a chemical reaction?
To me, that would sound like maybe one of the first two, but
knowing nothing about this, I am now firmly speculating :-)

And to make sense, -Ea/(RT) is always less then zero.  Reasonable
example: Ea = 30 kJ/mol, R=8.314, T=600 K gives you -6.01 as the
argument of the exponent, so the term is then ~ 0.002444 .

>
So, something like [-10:0] ?

Activation energies can also be 180 kJ/mol, but I don't really
know the range that people might want to calculate these values.