CHEMISTRY. 



43 



Elements 



of 

 Chemistry. 



Of pri- 

 mary com- 

 pound*. 



DIVISION I. 



Elements 

 of 



OF PRIMARY COMPOUNDS. 



THE primary compounds 

 as we are sufficiently well acquainted wit'i to 



such of them at least 

 intro- 

 duce here, may be arranged under the following heads : 



1. Alkalies. 



2. Earths. 



3. Oxides. 



4. Acids. 



5. Compounds of chlorine. 



6. Compound combustibles. 



These shall be the subject of the six following 

 Chapters. 



CHAP. I. 



Of Alkalies. 



THE term alkali was introduced into chemistry, af- 

 ter having been applied to a plant that still retains 

 the name of kali. When this plant is burnt, the ash- 

 es washed in water, and the water evaporated to dry- 

 ness, a white substance remains, called alkali. Al- 

 kali may be obtained from many other bodies besides 

 this plant. Chemists gradually discovered that dif- 

 ferent substances had been confounded together un- 

 der the name of alkali. The word, in consequence, 

 became general, and u now applied to all substances 

 having the following properties. 



Alkali ex. 1. A caustic taste. 



plained. 2. Volatilized by heat. 



3. Capable of combining with acids, and of de- 

 stroying their acidity. 



4. Soluble in water, even when combined with car- 

 bonic acid. 



'>. Capable of converting vegetable blues to green. 



The alkalies at present known are three in num- 

 ber ; 1. Ammonia; 2. Potash; 3. Soda. The first 

 is called volatile alkali ; the two \zsljixcd alkalies. 



SECT. I. Of Ammonia. 



Ammonia, p u t into a retort a mixture of three parts quick- 

 lime, and one part sal ammoniac; plunge the beak 

 of the retort into a trough filled with mercury. Ap- 

 ply heat. A gas comes over, which may be received 

 in glass jars filled with mercury. This gas is am- 

 monia. 



This gas possesses the mechanical properties of 

 common air. Its taste is acrid and pungent, and it 

 has a strong smell, not unpleasant when diluted. Ani- 

 mals cannot breathe it, and combustibles do not burn 

 in it. Its specific gravity is 0.600, that of air being 

 1.000. At the temperature of 60, 100 cubic inches 

 of it weigh 18.16 grains. When exposed to a cold 

 of 4-5, it is condensed into a liquid. When passed 

 through a red-hot tube, it is decomposed and convert- 

 ed into hydrogtii and azotic gases. 



Water absorbs it witli great rapidity. This liquid 

 absorbs 780 times its bulk of this gas ; and six parts 

 cf water, by tin* absorption, increase in bulk to 10 



how ob- 

 tained. 



It i proper- 



?arts. The specific gravity of this solution is 0.900. 

 t is in this state that ammonia is commonly used. It 

 was known to the alcliymists, and called hartuhurn, ._' _"/ 

 spirit of urine, and spirit of sal ammoniac. 



Ammoniacal gns is not altered by light, but when Composi- 

 electric sparks are made to pass through it, its bulk tion. 

 is nearly doubled, and it is converted into hydrogen 

 and azotic gases. Hence it follows, that it is com- 

 posed of hydrogen and azote. The most exact ex- 

 periments make the proportion of the constituents, 

 three parts, in bulk, of hydrogen gas, and one p art 

 of azote; or in weight, 



81.5 azote, 

 18.5 hydrogen. 



100.0 



When mixed with oxygen gas, it detonates by Action of 

 electricity, and is decomposed, as Dr Henry has as- ox yg en - 

 certained. To analyse ammonia by means of oxygen, 

 it ought to be first mixed with half its bulk of oxygen 

 gas. An electric spark occasions a combustion ; but 

 the whole of the hydrogen is not consumed. By 

 adding another quantity of oxygen gas, a new com- 

 bustion may be produced. Double the oxygen gas 

 consumed indicates the bulk of hydrogen, and the 

 azote remaining in the residuary gas, its bulk may be 

 estimated. 



When mixed with chlorine, it burns with consider- Chlorine: 

 able splendour ; and a quantity of sal-ammoniac is 

 formed at the same time. 



Sulphur is the only one of the simple combustibles Sulphur, 

 that combines with ammonia. The combination may 

 be produced by mixing it with sulphur in the state of 

 vapour, or better by distilling a mixture of equal 

 weights of sal-ammoniac, sulphur, and quick- lime di- 

 luted with a little water. A yellow liquid comes 

 over, which consists of water, holding in solution am- 

 monia and sulphur. It contains an excess of ammo- 

 nia. 



When ammonia comes in contact with phosphorus 

 at a red heat, it is decomposed, and phosphureted hy- 

 drogen gas formed. When ammoniacal gas is made 

 to pass through red-hot charcoal, a substance is form- 

 ed called pnissic acid. 



Ammonia is not acted on by azote. 



Ammonia is capable of oxidizing some of the me- Action of 

 tals, and of dissolving the oxides formed. Liquid metals, 

 ammonia dissolves the oxides of silver, copper, iron, 

 tin, nickel, zinc, bismuth, and cobalt. When digest- 

 ed upon the oxides of mercury, lead, or manganese, 

 it is decomposed, water formed, and azotic gas emit- 

 ted. It combines readily with the peroxides of gold 

 and silver ; and forms two remarkable compounds, 

 known by the names of fulminating gold and silver. 



Fulminating gold may be obtained by dissolving p u | m ina- 

 gold in aqua regia, and precipitating it by ammonia, ting gold. 

 A yellow precipitate falls, which is to be washed and 

 dried. It u fulminating gold. It is composed of 

 five parts yellow oxide of gold, and one part of am- 

 monia. It fulminates violently, when heated to the 

 temperature of about 300 or 400; also when struck 

 violently with a hammer, or when triturated in a mop- 

 tar. Water is formed, and azotic gas emitted. 



Fulminating silver was discovered by Berthollet. Fulruina- 

 It may be prepared by dissolving silver in uitric acid, 



