[shinagan]

Hi everyone,

I'm looking for the solubility of ammonia in water depending on the pressure and the temperature. It looks like it is related to Henry's law, but Henry's law gives a relationship between the concentration in the solution and the partial pressure of ammonia on top of the solution.
How do I find the partial pressure of ammonia?

[Borek]

How do I find the partial pressure of ammonia?

Depends on what data you have.

Do you know the definition of the partial pressure?

[shinagan]

Well I've found that it was
Pi = xi*Ptot
with Pi being the partial pressure, xi the molar fraction of the gas in the mix above the solution (the gas on top of the water would be a mix of H20 and NH3) and Ptot the total pressure. I know Ptot, but how can I determine xi then?

[Borek]

What is the problem that you are trying to solve?

As I said, what you have to do depends on what kind of data you have, it may happen that the problem can't be solved. So far you have not explained what you are doing.

[Enthalpy]

Ammonia in water is extensively tabulated and drawn because it's used in some fridges.

[Enthalpy]

A few sources:
http://www.engineeringtoolbox.com/gases-solubility-water-d_1148.html
(bookmark the Engineeringtoolbox site. Not perfect, but often useful.)
https://en.wikipedia.org/wiki/Solubility_table
(download it somehow)
https://www.google.de/search?q=ammonia+solubility+temperature&tbm=isch&tbo=u&source=univ

Plus the books that specialize in fridges.