A manual of chemistry, inorganic and organic : inorganic and organic, with an introduction to the study of chemistry / by Arthur P. Luff.

  • Luff, Arthur P. (Arthur Pearson), 1855-1938.
Date:
1892
Catalogue details

Licence: Public Domain Mark

Credit: A manual of chemistry, inorganic and organic : inorganic and organic, with an introduction to the study of chemistry / by Arthur P. Luff. Source: Wellcome Collection.

Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.

    94/558 (page 74)
    Both these metals only liberate one-half of the hydi-ogen of the Avater, uniting with tlie other half and with the oxygen to form respectively the hydrate of the metal, thus: Kg + 2H2O Potassium. Water. Na, + 2H2O Sodium. Water. = 2KH0 + H2 Potassium Hydrogen, hydrate. = 2NaH0 + H2 Sodium Hydrogen, hydrate. Properties.—Hydrogen is a colourless, tasteless, and odourless gas. It is the lightest body knoAvn, and its specific gravity is represented as 1, the spe- cific gravities of other gases representing the number of times they ai'e heavier than hydrogen ; air is 144 times heavier than hydrogen. The weight of a litre of hydrogen taken at 0° C. and 760 mm. barometric pressure is 0896 gramme, and is known as the critli (from )cpi0>/, a barleycorn) ; 1 gramme of hydrogen at 0° 0. and 760 mm. barometric pressure occupies 11 2 litres (this latter fact will be found extremely useful in converting weights of various gases into volumes). Hydrogen is combustible, burning with an almost in- visible flame if pure, and forming, by union with the oxygen of the air, water; it is a non-supporter of combustion. By the term combustion, as ordinarily employed, is meant union with the oxygen of the air, such union being accompanied by the production of heat and light, so that combustion may be defined as oxidation in which the chemical action is sufficiently great to be accompanied by the evident production of heat and light. It must, however, be clearly understood that the terms combustible and supporter of combustion are purely relative; thus, hydrogen is combus-