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Because aqueous ammonia is a gas dissolved in water, as the water evaporates from a surface, the gas evaporates also, leaving the surface streak-free. Its most common uses are to clean glass, [10] porcelain, and stainless steel. It is good at removing grease and is found in products for cleaning ovens and for soaking items to loosen baked-on grime.
Liquid ammonia has a very high standard enthalpy change of vapourization (23.5 kJ/mol; [28] for comparison, water's is 40.65 kJ/mol, methane 8.19 kJ/mol and phosphine 14.6 kJ/mol) and can be transported in pressurized or refrigerated vessels; however, at standard temperature and pressure liquid anhydrous ammonia will vaporize.
The table above gives properties of the vapor–liquid equilibrium of anhydrous ammonia at various temperatures. The second column is vapor pressure in kPa. The third column is the density of the liquid phase. The fourth column is the density of the vapor. The fifth column is the heat of vaporization needed to convert one gram of liquid to vapor.
For example, the limiting acid in liquid ammonia is the ammonium ion, NH 4 + which has a pK a value in water of 9.25. The limiting base is the amide ion, NH 2 −. NH 2 − is a stronger base than the hydroxide ion and so cannot exist in aqueous solution. The pK a value of ammonia is estimated to be approximately 34 (c.f. water, 14 [3] [4]).
For an example, see Ice § Phases. Liquid: A mostly non-compressible fluid. Able to conform to the shape of its container but retains a (nearly) constant volume independent of pressure. Gas: A compressible fluid. Not only will a gas take the shape of its container but it will also expand to fill the container.
A vapor can exist in equilibrium with a liquid (or solid), in which case the gas pressure equals the vapor pressure of the liquid (or solid). A supercritical fluid (SCF) is a gas whose temperature and pressure are above the critical temperature and critical pressure respectively. In this state, the distinction between liquid and gas disappears.
Ammonia electrolysis may require much less thermodynamic energy than water electrolysis (only 0.06 V in alkaline media). [23] Another option for recovering ammonia from wastewater is to use the mechanics of the ammonia-water thermal absorption cycle. [24] [25] Ammonia can thus be recovered either as a liquid or as ammonium hydroxide. The ...
Ammonia pollution is pollution by the chemical ammonia (NH 3) – a compound of nitrogen and hydrogen which is a byproduct of agriculture and industry. Common forms include air pollution by the ammonia gas emitted by rotting agricultural slurry and fertilizer factories while natural sources include the burning coal mines of Jharia , the caustic ...