Ammonia, properties

Ammonia is a colorless, flammable, toxic, alkaline gas. Its water solution is alkaline because much of the dissolved ammonia reacts with water (H20) to form ammonium hydroxide (NH4OH), which is a weak base. 

Ammonia dissolves alkali metals, barium, calcium and strontium and forms an unstable blue solution. This solution contains the metal ion and free electrons that slowly decompose, release hydrogen and form the metal amide. Compared to water, liquid ammonia is less likely to release protons (H+ ions), is more likely to take up protons (to form NH4+ ions) and is a stronger reducing agent219. 

Ammonia takes part in many chemical reactions. Ammonia reacts with strong acids to form stable ammonirun salts219  

Ammonium salts of weak acids are readily decomposed into the acid and ammonia. Ammonium carbonate [(NH3)2co3 h2oj is a colorless-to-white crystalline solid commonly known as smelling salts. In a water solution it is sometimes called aromatic spirits of ammonia . Ammonia also reacts with Lewis acids (electron acceptors) such as sulfur dioxide or sulfur trioxide or boron trifluoride219. 

Another kind of reaction, commonly called ammonolysis, occurs when one or more of the hydrogen atoms in the ammonia molecule is replaced by some other atom or radical. For example, chlorine gas (Cl2) reacts directly with ammonia to form monochloramine (NH2C1) and hydrogen chloride (HC1)219. 

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Most recent tabulations of ammonia properties are based upon the extensive tabulation to 5000 bar, 750 K of Haar, L. and J. S. Gallagher, y. Fhys. Chem. Ref Data, 7, 3 (1978) 635-792, which does, however, neglect dissociation. For tables to 70,000 psia, 920 F, see Stewart, R. B., R. T. Jacobsen, et al., Theimodynamic Fiopeiiies of Reft igei ants, ASHRAE, Atlanta, GA, 1986 (521 pp.). A chart in fps units corresponding witb these tables appears on page 17.34 of the ASHRAE 1989 Fundamentals Handbook. 

Ammonia Properties, www.encvcloDedia.com/articles/00445ProDerties.html. The Columbia Electronic Encyclopedia, Sixth Edition, Columbia University Press, 2000. 

FIG 2-6 Pressure-enthalpy diagram for ammonia. Properties computed with the NIST REFPROP Database, Version 7.0 (Lemmon, E. W., McLinden, M. O., and Huber, M. L., 2002, NIST Standard Ref- erence Database 23, NIST Reference Fluid Thermodynamic and Transport Properties—REFPROP, Version 7.0, Standard Reference Data Program, National Institute of Standards and Technology), based on... 

The amount of dextranase attached to porous titanium(iv) oxide by chelation increased in the presence of ammonia, although more enzyme specific activity was retained in the absence of ammonia. Properties of the immobilized enzyme include a pH-dependence and reversibility of the coupling between the enzyme and the matrix. 

Features Stable to Inorg. builders, alkalis, and aqua ammonia Properties Water-wh. to pale yel. thin liq., mild odor misc. with water sp.gr. 0.93 flash pt. (COC) 204 F pH 7.7 0.3 95+% act. 

Uses Surfactant for drapery foam and coatings, uphoistery backing, fiiier coatings, fiiter media saturants intermediate for conversion to metai stearates Features Low ammonia Properties 32% act. 

A new dimension to acid-base systems has been developed with the use of zeolites. As illustrated in Fig. XVIII-21, the alumino-silicate faujasite has an open structure of interconnected cavities. By exchanging for alkali metal (or NH4 and then driving off ammonia), acid zeolites can be obtained whose acidity is comparable to that of sulfuric acid and having excellent catalytic properties (see Section XVIII-9D). Using spectral shifts, zeolites can be put on a relative acidity scale [195]. An important added feature is that the size of the channels and cavities, which can be controlled, gives selectivity in that only... 

The concept of two-state systems occupies a central role in quantum mechanics [16,26]. As discussed extensively by Feynmann et al. [16], benzene and ammonia are examples of simple two-state systems Their properties are best described by assuming that the wave function that represents them is a combination of two base states. In the cases of ammonia and benzene, the two base states are equivalent. The two base states necessarily give rise to two independent states, which we named twin states [27,28]. One of them is the ground state, the other an excited states. The twin states are the ones observed experimentally. 

The alkali metals have the interesting property of dissolving in some non-aqueous solvents, notably liquid ammonia, to give clear coloured solutions which are excellent reducing agents and are often used as such in organic chemistry. Sodium (for example) forms an intensely blue solution in liquid ammonia and here the outer (3s) electron of each sodium atom is believed to become associated with the solvent ammonia in some way, i.e. the system is Na (solvent) + e" (sohem). 

Ammonia is a colourless gas at room temperature and atmospheric pressure with a characteristic pungent smell. It is easily liquefied either by cooling (b.p. 240 K) or under a pressure of 8-9 atmospheres at ordinary temperature. Some of its physical and many of its chemical properties are best understood in terms of its structure. Like the other group head elements, nitrogen has no d orbitals available for bond formation and it is limited to a maximum of four single bonds. Ammonia has a basic tetrahedral arrangement with a lone pair occupying one position ... 

Ferrate(VI) has powerful oxidising properties, for example ammonia is oxidised to nitrogen. Potassium ferratefVI) is isomorphous with potassium chromatefVI), and both anions are tetrahedral. 

Phenylhydrazine on exposure to light slowly darkens and eventually becomes deep red in colour salts of the base share this property but to a lesser degree, the sulphate and acetate (of the common salts) being most stable to light. Phenylhydrazine is largely used in organic chemistry to characterise aldehydes and ketones as their phenyl-hydrazones (pp. 342, 345), and carbohydrates as their osazones (pp. 136-140). It is readily reduced thus in the process of osazone formation some of the phenylhydrazine is reduced to aniline and ammonia. On the... 

Hydrolysis of a nitrile to an acid. Reflux 1 g. of the nitrile with 6 ml. of 30-40 per cent, sodium hydroxide solution until ammonia ceases to be evolved (2-3 hours). Dilute with 5 ml. of water and add, with coohng, 7 ml. of 50 per cent, sulphuric acid. Isolate the acid by ether extraction, and examine its solubility and other properties. 

These monomers provide a means for introducing carboxyl groups into copolymers. In copolymers these acids can improve adhesion properties, improve freeze-thaw and mechanical stability of polymer dispersions, provide stability in alkalies (including ammonia), increase resistance to attack by oils, and provide reactive centers for cross-linking by divalent metal ions, diamines, or epoxides. 

Some of the physical properties of fatty acid nitriles are Hsted in Table 14 (see also Carboxylic acids). Eatty acid nitriles are produced as intermediates for a large variety of amines and amides. Estimated U.S. production capacity (1980) was >140, 000 t/yr. Eatty acid nitriles are produced from the corresponding acids by a catalytic reaction with ammonia in the Hquid phase. They have Httie use other than as intermediates but could have some utility as surfactants (qv), mst inhibitors, and plastici2ers (qv). 

Urea can be considered the amide of carbamic acid, NH2COOH, or the diamide of carbonic acid, CO(OH)2. At room temperature, urea is colorless, odorless, and tasteless. Properties are shown ia Tables 1—4. Dissolved ia water, it hydrolyzes very slowly to ammonium carbamate (1) and eventually decomposes to ammonia and carbon dioxide (qv). This reaction is the basis for the use of urea as fertilizer (qv). 

Table 3. Properties of Saturated Solutions in Urea in Ammonia ...

Physical Properties. The physical form and stabiUty of a fertilizer product is of an importance almost equal to that of its chemical content. Commercial fertilizers of importance include not only soHds, but also fluids, both solutions and suspensions, and even a gas (anhydrous ammonia). 

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