Hydrogen

Description

The lightest of all chemical elements. Hydrogen is a colorless, odorless and tasteless gas. Although it is considered the most abundant element in the universe, it is only present in the earth's atmosphere at a concentration of 50 ppm. Most of the hydrogen on earth is in the form of water. It is the primary source of energy in the sun and stars. Hydrogen was first recognized as an element by Cavendish in 1766 and named by Lavoisier in 1783. Hydrogen is used in rocket fuels, in balloon, in welding torches and in the production of ammonia and methanol.

Synonyms and Related Terms

H; inflammable gas (prior to 1800); Waterstof (Ned.); Waterstof (Fr.); Wasserstoff (Deut.); idrogeno (It.); Hidrogênio (Port.); hidrógeno (Esp.); Väte (Sven.)

Risks

• Highly flammable and explosive.
• An asphyxiant at high concentrations.
• Airgas: SDS

Physical and Chemical Properties

• Slightly soluble in water, ethanol and ether.
• Burns with a pale blue flame.

Composition	H (atomic no. 1)
CAS	1333-74-0
Melting Point	-259.2 C
Molecular Weight	atomic wt = 1.0079
Boiling Point	-252.77 C

Resources and Citations

• Web Elements: Website

• Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976

• Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997

• The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998

• Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993

• The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry # 4833

• Susan E. Schur, Conservation Terminology: A review of Past & Current Nomenclature of Materials, Technology and Conservation, Spring (p.34-39); Summer (p.35-38); Fall (p.25-36), 1985