By the addition of sulphuretted hydrogen to the nitriles, or by the action of phosphorus pentasulphide on the acid-amides.
By heating the disulphide in a current of hydrogen, germanious sulphide, GeS, is formed.
Volcanic sulphur usually occurs as a sublimate around or on the walls of the vents, and has probably been formed in many cases by the interaction of sulphur dioxide and hydrogen sulphide.
In order to get rid of hydrogen, some oxygen is added to the helium, and the mixture exploded by an electric spark.
It is readily oxidized by nitric acid, and when strongly heated_ in a current of hydrogen is reduced to the metallic condition.
His researches on sebacic acid (1802) and on bile (1807), and his discovery of peroxide of hydrogen (1818) also deserve mention.
A pentasulphide B2S5 is prepared, in an impure condition, by heating a solution of sulphur in carbon bisulphide with boron iodide, and forms a white crystalline powder which decomposes under the influence of water into sulphur, sulphuretted hydrogen and boric acid.
It does not melt at a white heat, and is easily reduced to the metal by heating in a current of hydrogen or with carbon.
It can also be determined as sulphide, by precipitation with sulphuretted hydrogen, the precipitated sulphide being dried at Ioo° C. and weighed.
Molybdenum trisulphide, MoS3, is obtained by saturating a solution of an alkaline molybdate with sulphuretted hydrogen and adding a mineral acid.
The original hypothesis of Baeyer suggested that the course of events is the following: the carbon dioxide is decomposed into carbon monoxide and oxygen, while water is simultaneously split up into hydrogen and oxygen; the hydrogen and the carbon monoxide unite to form formaldehyde and the oxygen is exhaled.
The formaldehyde at once undergoes a process of condensation oi- polymerization by the protoplasm of the plastid, while the hydrogen peroxide is said to be decomposed into water and free oxygen by another agency in the cell, of the nature of one of the enzymes of which we shall speak later.
It may be obtained from argyrodite by heating the mineral in a current of hydrogen; or by heating the dioxide to redness with carbon.
It can also be obtained by passing sulphuretted hydrogen through a solution of the dioxide in hydrochloric acid.
Deposits of sulphur are frequently formed by the decomposition of hydrogen sulphide, on exposure to the atmosphere: hence natural sulphureous waters, especially hot springs, readily deposit sulphur.
At low temperatures, on the other hand, they find, using an initial pressure of 'coo mm., that the temperatures on the helium scale are measurably higher than on the hydrogen scale, owing to the more perfectly gaseous condition of helium.
It is used as a pigment (cadmium yellow), for it retains its colour in an atmosphere containing sulphuretted hydrogen; it melts at a white heat, and on cooling solidifies to a lemon-yellow micaceous mass.
In water and in ethylene experiment shows that 8 parts by weight of oxygen and 6 parts of carbon, respectively, are in union with one part of hydrogen; also, if the diagrams are correct, these numbers must be in the ratio of the atomic weights of oxygen and carbon.
Necessary to determine the specific gravities of the various gases referred to some one of them, say hydrogen; the numbers so obtained giving the weights of the molecules referred to that of the hydrogen molecule.
Poulsen immensely improved this process by placing the arc in an atmosphere of hydrogen, coal-gas or some other nonoxidizing gas, and at the same time arranging it in a strong magnetic field.'
The electric arc is formed between cooled copper (positive) and carbon (negative) electrodes in an atmosphere of hydrogen or coal-gas.
Cadmium vapour decomposes water at a red heat, with liberation of hydrogen, and formation of the oxide of the metal.
Cadmium sulphide, CdS, occurs naturally as greenockite (q.v.), and can be artificially prepared by passing sulphuretted hydrogen through acid solutions of soluble cadmium salts, when it is precipitated as a pale yellow amorphous solid.
The hydrogen of the hydroxyl group in phenol can be replaced by metals, by alkyl groups and by acid radicals.
Heated at 190-300° in a current of hydrogen it gives the oxide C0304, while at higher temperatures the monoxide is formed, and ultimately cobalt is obtained.
He determined the percentages of carbon, hydrogen and oxygen in the sugar and in the products of fermentation, and concluded that sugar in fermenting breaks up into alcohol, carbonic acid and acetic acid.
It is decomposed by water, and with a solution of yellow phosphorus in carbon bisulphide it gives a red powder of composition PBI 2, which sublimes in vacuo at 210° C. to red crystals, and when heated in a current of hydrogen loses its iodine and leaves a residue of boron phosphide PB.
On fusion with solid potash at 250° C. it completely decomposes, giving potassium oxalate and hydrogen, C2H602-1-2KHO =K2C204+4H2.
Trans., 18 53, p. 357, 18 54, p. 321, and 1862, p. 579) showed that the statement that no internal work is done when a gas expands or contracts is not quite true, but the amount is very small in the cases of those gases which, like oxygen, hydrogen and nitrogen, can only be liquefied by intense cold and pressure.
Cadmium salts can be recognized by the brown incrustation which is formed when they are heated on charcoal in the oxidizing flame of the blowpipe; and also by the yellow precipitate formed when sulphuretted hydrogen is passed though their acidified solutions.
Sulphur is present to the extent of more than i %, whence the smell of suiphuretted hydrogen when the resin is heated.