Properties of Ammonia

Erom thermodynamic properties of ammonia greater than a datum of -40°E ... 

Figure 11-17A. Thermal properties of ammonia-water solutions. (Used by permission Rescorla, C. L and Miller, D. K. Plant Engineering Handbook, 2"= Ed., Figure 14-7. McGraw-Hill, Inc. All rights reserved.)...

Figure 12-24A. Mollier chart for properties of ammonia. (Used by permission Dept, of Commerce, U.S. Bureau of Standards.)...

Thus we find that each of these gases has distinctive properties. If these gases are made up of particles, then the particles must be distinctive. The particles that are present in ammonia cannot be like the particles in hydrogen chloride, or like those in the other gases. The nature of the ammonia particles, then, is the key to the properties of ammonia. The particles that make up a gas determine its chemistry. They are so important to the chemist that they are given a special name. A gas is described as a collection of particles called molecules. 

On the above basis it is, in principle, unnecessary to treat the strength of bases separately from acids, since any protolytic reaction involving an acid must also involve its conjugate base. The basic properties of ammonia and various amines in water are readily understood on the Bronsted-Lowry concept. 

The dangerous behaviour of this substance vis-a-vis various reagents can be explained by the basic properties of ammonia. 

Among the physical properties of ammonia the outstanding features are its solubility in water, its absorption by charcoal, and its liquefaction. 

Unlike the Arrhenius theory, the Bronsted-Lowry theory of acids and bases can explain the basic properties of ammonia when it dissolves in water. See Figure 8.4. 

General properties of ammonia are discussed in Mellot(Ref 6), Gmelin(Ref 13), Thorpe(Ref 15),ChemRevs(Ref 17a), Kirk Othmer(Ref 32) and in Ullmann(Ref 59). Franklin(Ref 1) described the reactions of liq ammonia Von Braun et al(Ref 16) reported a violent and explosive reaction of liq ammonia with some organic halogen compds. For example, when the reaction between liq ammonia and BrHaC—CHaBr was carried out at RT, there occurred a spontaneous evolution of heat resulting in a violent expln. 

Claus propositions were summarized as three statements in his more widely read paper of 1856 42 (1) If several equivalents of ammonia (from two to six) combine with an equivalent of certain metal chlorides, neutral substances are formed, in which the basic property of ammonia has been destroyed and simultaneously the ammonia can be neither detected by the usual methods nor eliminated by double decomposition . (2) If the chlorine in these compounds is replaced by oxygen, strong bases are obtained, whose saturation capacity is always determined by the oxygen equivalents contained in them but not by the number of equivalents of ammonia present in them . (3) The number of equivalents of ammonia entering into these substances is not a random one as is evident from a number of facts, it is determined by the number of equivalents of water contained in the hydrates of the metal oxides which can enter into such compounds along with the ammonia . 

Amines, RNH2, are structurally related to ammonia, NH3, and we therefore may predict that they will have similar properties. A property of ammonia that you probably will have encountered earlier is that it acts as a... 

Natl. Bur. Standards, Tables of Thermodynamic Properties of Ammonia, Circ. 142... 

Bassam Z. Shakhashiri, "Preparation and Properties of Ammonia/ Chemical Demonstrations, A Handbook for Teachers of Chemistry, Vol. 2 (The University of Wisconsin Press, Madison, 1985), pp. 202-204. Ammonia gas is produced from the reaction of ammonium chloride with calcium hydroxide and is collected in an Erlenmeyer flask by the displacement of air. The ammonia gas turns moistened litmus paper blue, demonstrating the basic properties of ammonia dissolved in water. When the mouth of an ammonia-filled Erlenmeyer flask is placed below the surface of a pool of water, water rapidly enters the flask to replace ammonia that dissolves in the water. White smoke forms when ammonia vapor is passed over the top of a beaker of concentrated hydrochloric acid forming solid ammonium chloride. 

Making ammonia in the laboratory Physical properties of ammonia Chemical properties of ammonia... 

Don t become confused by memorizing too much detail about the physical properties of ammonia and amines. For the MCAT, just Keep in mind that ammonia and amines hydrogen bond, which raises boiling point and increases solubility. 

Some of the physical properties of ammonia are listed in Table 8.1 and Table 8.2. 

Doering, R., "Thermophysical Properties of Ammonia (R717) and of Fluorinated Refrigerants Rll and R113," pp. 574-588, in Proceedings of the 7th Symp. on Thermophys. Prop., National Bureau of Standards, Gaithersburg, MD, published by ASME, NY, May (1977). 

The method of reduction influences the properties of ammonia catalysts. A generally appropriate reduction schedule cannot be prescribed because different types of catalysts call for different reduction procedures to reach their most active state. It has previously been mentioned that the promoters used in ammonia catalysts have a retarding effect on the reduction. According to the author s experience, oxides of the alkaline earth metals, especially CaO, make the catalysts especially difficult to reduce. As will be remembered these oxides enter the magnetite matrix readily. 

---