|
|
OXYGEN (image O, atomic weight 16), a non-metallic chemical component. It was apparently first obtained in 1727 by Stephen Hales by strongly heating minium, but he doesn't appear to have acknowledged that he had obtained a brand new component, and the first published description of its properties was resulting from J. Priestley in 1774, who obtained the gasoline by igniting mercuric oxide, and gave it the title "dephlogistigated air." K. W. Scheele, working independently, additionally announced in 1775 the invention of this component which he known as "empyreal air" (Crells’ Annalen, 1785, 2, pp. 229, 291). A. L. Lavoisier repeated Priestley’s experiments and named the fuel "oxygen" (from Gr. Oxygen occurs naturally as one of many chief constituents of the environment, and in combination with different elements it's present in very massive portions; it constitutes approximately eight-ninths by weight of water and practically one-half by weight of the rocks composing the earth’s crust. It is also disengaged by rising vegetation, plants possessing the facility of absorbing carbon dioxide, assimilating the carbon and rejecting the oxygen.
my blog :: BloodVitals SPO2 |
|
发表于