What is the vapour pressure of 100 ppm of ammonia in water.?

Question

If any one can help, I would be grateful. I would be interested in how this is calculated or where I can find the data.

Answer 1

This is waay over my head, but from what I could get from my physical chemistry text book vapour pressure depends on the volume of the liquid (work out from concentration of NH3 and volume of water) and the volume which the evaporated gas occupies. The atmospheric pressure comes into play if it is not in a sealed container, as the volume of gas increases so does the pressure the volume of evaporated gase will increase until equilibrium is reached. Vapour pressure changes as a function of temperature.

Further reading:
http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/vappre.html#c2
http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/vapcon.html#c1

http://www.chemguide.co.uk/physical/phaseeqiamenu.html#top

Answer 2

every time you do a water change the ammonia in your tank should spike a bit then go back down. This is because most water conditioners only dechlorinate water, and when that happens chlorine is converted into ammonia. Every single water conditioner out there would do this, but your fish will be fine if you use a water conditioner that also has an ammonia/nitrite/nitrate binder. It will still show up in a test, but your fish will not be affected by it at all so your tank can go through a mini-cycle again but without stressing or harming your fish. Kordon's Amquel/+ and Seachem's Prime all do this so if you aren't already using these, I'd highly recommend them.

Answer 3

You need to look up the Henry's Law constant for ammonia. You should be able to work it out from there, converting units if necessary.

At a guess, I would say not much, given how soluble ammonia is in water.