Text-book for students of chemistry. Containing a condensed view of the facts and the principles of the science / [D.B. Reid].

  • David Boswell Reid
Date:
1836
Catalogue details

Licence: Public Domain Mark

Credit: Text-book for students of chemistry. Containing a condensed view of the facts and the principles of the science / [D.B. Reid]. Source: Wellcome Collection.

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    825. Tests_Ammonia is easily recognised in solution by the very deep and brilliant blue colour which it gives to solutions containing copper (see Copper). When combined with an acid, it may be disengaged by potassa, soda, or lime, which retain the acid previously combined with it, v/hile a gentle heat causes the ammonia to be expelled in the gaseous form. In this condition it may be recog¬ nised by the white fumes it produces with nitric, carbonic, or muriatic acids, and by its alkaline reaction on turmeric paper, which it turns to a brown, and on cabbage paper, which becomes green; a very slight heat is sufficient to restore the original colour of the test paper, the ammonia being expelled. 826. Ammonia has all the characteristic properties of an alkali, though differing so widely from the common alkalis in its composition. It has a verj’- acrid alka¬ line taste; corrodes animal and vegetable matters; affects the blue colouring matter of cabbage and violets, and also turmeric, in the same manner as potassa; neutralizes the acids and forms salts; these, however, are either decomposed or volatilized by a red heat. From its volatility it is often termed the volatile ALKALI; potassa, soda, and lithia, being denominated fixed alkalis. 827. Preparation.—Ammonia is procured from animal substances ; these are subjected to a red heat, and the gas evolved is condensed in water. The proximate princijiles of the animal kingdom are almost all composed of carbon, oxygen, hy¬ drogen, and nitrogen. Subjected to heat when the air is excluded, their elements assume a new arrangement, and part of their hydrogen and nitrogen combining together, ammonia is the product, chiefly in union with carbonic acid. By com¬ bining it with muriatic acid, and separating it again by means of potassa. soda, or lime, it is procured free from any empyreumatic odour, and in the condition in which it is condensed by water to afford the purest ammonia. In conducting this part of the process, muriate of ammonia is generally mixed with slaked lime, and the ammoniacal gas disengaged by the action of heat is condensed in water kept very cold; the nature of the action is particularly explained in the diagram page 4, where the proportion of materials that affect each other, and of the products formed, is pointed out. Symb. HCl+NH3&-Ca = ClCa&'H&NH^. Compounds of Ammonia. 828. Nitrate of Ammonia—Symb. ; iN+NH^ = nitric acid 54 -f ammonia 17. Eq. 71_Symb. of Cr. Nitrate of Ammonia = ’H-f (: :N+NH^ = wa¬ ter 9 + nitrate of ammonia 71 =• Eq. 80. 829. Very deliquescent, produces great cold during solution in water, crystal¬ lizes in prisms, when evaporated at a temperature not exceeding 100°; a fibrous mass is procured if it be evaporated at 212°; and when fused by heat continued so that it acquires a temperature of 300° or upwards, it becomes quite compact on cooling. 830. Its decomposition, so as to produce nitrous oxide, has been already noticed, ])ar. 470 ; when subjected suddenly to a red heat, it deflagrates with rapidity, the hydrogen of the ammonia uniting with part of the oxygen of the nitric acid, and forming water. 831. Sulphate of Ammonia.—Symb. :S4-NH^ = sulphuric acid 40 + ammo¬ nia 17. Eq. 57—Prepared easily by neutralizing dilute sulphuric acid with am¬ monia or its carbonate, carbonic acid being disengaged when the carbonate is used. It is found in soot, associated with sulphite of ammonia, the sulphur of the acid being derived from the iron-pyrites so frequently met with in coal, and the am¬ monia formed by the decomposition of the bituminous matter. Soluble in water, crystallizes in 6-sided prisms. 832. Hydrosulphate or Hydrosulphuket of Ammonia.—HS-fNH’ =0
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