hydrogen

[Gr. hydōr =water, and gennaō to generate, to produce.] Chem.: Hydrogenium. A monatomic metallic ele ment, which exists in the state of gas. Symbol H; atomic weight, 1; density, 0-06927; air being 1; weight of a liter of hydrogen, 0.0896 grammes, called hydrokinetics sis of water, H2O, the H being liberated at the platinum pole; by the action of metallic sodium and water; also by pa ing steam over iron filings, 3Fe+4HOH=Fe3O4+8H; by boiling zinc with caus tic potash, 2KHO+Zn=K2ZnO2+2H; but His gen. erally made by the action of dilute H2SO4 on zinc. Hydrogen can be purified by pa ing it through a solution of two parts of K2Cr2O7 in twenty parts of water and one part of H2SO4, then washing it with KHO, and drying it by pa ing it through concen trated H2SO4. The apparatus should be airtight and the gas rejected till the air is all displaced by hydrogen. Hydrogen is absorbed by red-hot iron and platinum; palladium absorbs 935 times its volume of hydrogen; about seven liters of gas are condensed into the space 1 c.c. Graham called this an alloy of hydrogenium, a metal having the specific gravity of 0.62 and magnetic properties. Hydrogen has been found occluded in meteoric iron, and is contained in the gases given off by volcanoes. The spectroscope shows that a large quantity of free hydrogen exists around the sun. The spectrum of hydrogen contains four bright lines, a red arc corresponding to C, and a greenish-blue to F in the solar spectrum, and a blue and indigo line. Hydrogen has been condensed by Pictet, of Geneva, at a temperature of - 140, and at a pre ure of 650 atmospheres. When the pre ure is removed the hydrogen is evolved in a jet of a steel-blue color. Pure hydrogen is a colorle , inodorous, tastele is inflammable mixed with oxygen; it Explodes in contact with a flame, or when the elecca tric spark is pa ed through it, forming water. The calorific power of H is 34,462 thermal units. Hydrogen gas cannot support life, but it is not poisonous; it is slightly soluble in water. Hydrogen when kept in a bag for a long time is dangerous, owing to diffusion. One volume of hydrogen mixed with 25 volumes of air gives the loudest detonation. Hydrogen, in the nascent state is used as a reducing agent in chemistry. washed by pa ing it through water. Granulated zinc and fragments of native PbS acted upon with dilute HCl gives off a regular current of H2S. Hydrogen-sulphide is a colorle inflammable gas, of a sweetish taste and odor of rotten eggs. It is a narcotic poison. It burns with a blue flame, formH2S and three volumes of oxygen explodes violently on sending an electric spark through it. Chlorine decomposes it, the whole of the sulphur being separated; this is the best antidote to poisoning by H2S. Water at 0 di olves 4'37 volumes, at 15° 3-23 volumes of HS. The solution reddens blue litmus paper; it decomposes in the air, sulphur being deposited. H2S in contact with a base and a moist atmosphere is partially converted into H2SO4. At a pre ure of seventeen atmospheres at 10 hydrogen sulphide is reduced to a liquid, which boils at -61; it freezes at 85°. CO2 liberates H2S from a moist sulphide; the composition of H2S can be shown by heating metallic tin in a given volume of the gas; the sulphur unites with the tin, and the hydrogen liberated occupies the same volume as the original gas. H2S is used as a test for metals; if the sulphide is soluble in acids, it is not precipitated till the solution is neutralized, as free acid is liberated by the H2S, as ZnSO4+H2S=ZnS+H2SO4. The sulphides of the alkaline earths Ba, Sn, Cn, and Mg, and those of the alkalies are soluble in water. hydrogen-telluride, s. Chem.: H2Te, a gas prepared by the action of hydrochloric acid on zinc telluride. Called also Tel lur hydric acid, Hydro telluric acid, and Telluretted hydrogen. hy-drog-en-āte, hy-drog-en-ize, v. t. [Eng., ., hydrogen; -ate, -ize.] Chem.: To cause to combine with hydrogen. ly-dro-gen-1-ŭm, s. [HYDROGEN.] ry-drog-ěn-ize, v . t . [HYDROGENATE.] hy-drog-ěn-ous, a. [Eng., ., hydrogen; -ous.] Chem.: Of, belonging to, or containing hydrogen. hỹ-drog-no-sỹ, s. [Pref. hydro- (1), and Greek gnosis knowledge; gignōskō -to know.] A treatise on, or a history and description of the waters of the earth.