Look up: hydrogen

1. 
   hydrogen
   The lightest and most abundant element. A hydrogen atom consists of one proton and one electron. A hydrogen nucleus is just a single proton. Hydrogen composes about 75 percent of the Sun but only a tiny fraction of the Earth.
   Found on http://antwrp.gsfc.nasa.gov/apod/lib/glo
   
   
2. 
   Hydrogen
   Hydrogen is a non-metallic gaseous element with the symbol H. In its free gaseous state it is only found in nature in small quantities issuing from crevices in volcanic districts or near petroleum wells. It exists in combination everywhere; as a constituent of water, of all plants and animals, and in numerous minerals, abundantly in coal, petroleum, bitumen, etc., and to a lesser degree in rocks. The element may be separated from any of its compounds, but it is usually obtained from water or dil...
   Found on http://www.encyclo.co.uk/nol.php
   
   
3. 
   hydrogen
   [n] - a nonmetallic univalent element that is normally a colorless and odorless highly flammable diatomic gas
   Found on http://www.webdictionary.co.uk/definitio
   
   
4. 
   Hydrogen
   Lightest of gases H2. Combined with oxygen = water, combined with carbon = hydrocarbons. Element H
   Found on http://www.anson.co.uk/oilfield_glossary
   
   
5. 
   Hydrogen
   The least dense element. It has metallic and non-metallic properties. The most abundant element in the universe. Hydrogen occurs as H₂ at ambient temperature and pressure, a colourless, odourless, and extremely flammable gas. In its free gaseous state it is only found in nature in small quantities issuing from crevices in volcanic areas ...
   Found on http://www.diracdelta.co.uk/science/sour
   
   
6. 
   Hydrogen
   H The lightest gaseous element, and simplest of all atoms, occurring rarely in nature as a single atom, but common in the form of water, and in all organic compounds
   Found on http://www.bio-power.co.uk/glossary.htm
   
   
7. 
   Hydrogen
   Discovered : by Henry Cavendish in 1766Isolated in London, UKOrigin : The name is derived from the Greek ‘hydro genes`, meaning water forming.Description :A colourless, odourless gas that burns and can form an explosive mixture with air. It is currently manufactured from methane gas, but is also produced by the electrolysis of water and aqueous sal...
   Found on http://www.allchemicals.info/index/actio
   
   
8. 
   hydrogen
   (H) H; protium. Element 1, atomic weight 1.00797. The most abundant element in the universe. Hydrogen occurs as H₂ at ambient temperature and pressure, a colorless, odorless, and extremely flammable gas. Discovered in 1766 by Cavendish.
   Found on http://antoine.frostburg.edu/chem/senese
   
   
9. 
   Hydrogen
   The simplest element. Atomic Number 1. Hydrogen gas has a specific gravity of 0.0694 (air = 1), so it is much lighter than air. Hydrogen is highly flammable, forming water upon combustion. Explosive limits are 4% to 75%
   Found on http://www.fire.org.uk/glossary.htm
   
   
10. 
    Hydrogen
    The lightest known gas which has been, and still is, extensively used in airships and balloons. Its one great drawback is that it is highly inflammable and this undesirable characteristic has been the cause of many disasters. Because of this the heavier gas, helium, is more suitable for airship use.
    Found on http://www.aeroplanemonthly.com/glossary
    
    
11. 
    Hydrogen
    The lightest of the chemical elements, gaseous, colourless, odour-less and tasteless.
    Found on http://www.gadsbywicks.co.uk/docs/GLOSSA
    
    
12. 
    Hydrogen
    Hydrogen: The most plentiful element in the universe and one present in all organic compounds. Hydrogen is a gas with an atomic number of 1 and the symbol H. Two isotopes of hydrogen -- deuterium and tritium -- have been used as tracers in metabolic studies. Tritium is a long-lived weak emitter of radiation and can be easily incorporated in large m ...
    Found on http://www.medterms.com/script/main/art.
    
    
13. 
    hydrogen
    chemical element:atomic number 1 Category: Chemistry
    Found on http://www.mijnwoordenboek.nl/definition
    
    
14. 
    Hydrogen
    Hy'dro·gen noun [ Hydro- , 1 + -gen : confer French hydrogène . So called because water is generated by its combustion. See Hydra .] (Chemistry) A gaseous element, colorless, tasteless, and odorless, the lightest known substance, being fourteen and a half times lighter than air (hence its use in filling balloons), and over eleven thousand times lighter than water. I ...
    Found on http://www.encyclo.co.uk/webster/H/76
    
    
15. 
    hydrogen
    <chemistry, element> Hydrogen is a gas element which has an atomic number of 1 and an atomic weight of 1.0079. It combines with oxygen to form water (H20) and is present in all organic compounds. A few types of bacteria can metabolise atmospheric hydrogen (H2). Hydrogen gas itself is not poisonous, but when it mixes with air it can easily ign ...
    Found on http://www.mondofacto.com/facts/dictiona
    
    
16. 
    Hydrogen
    `Hydrogen` , is the chemical element represented by the symbol `H` and an atomic number of 1. At standard temperature and pressure it is a colourless, odorless, nonmetallic, tasteless, highly flammable diatomic gas (H2).
    Found on http://en.wikipedia.org/wiki/Hydrogen
    
    
17. 
    hydrogen
    (H) (hi´dro-jәn) a chemical element, atomic number 1, atomic weight 1.00797. It exists as the mass 1 isotope (protium, or light or ordinary hydrogen), mass 2 isotope (deuterium, heavy hydrogen), and mass 3 isotope (tritium). hydrogen cyanide an extremely...
    Found on http://www.mercksource.com/pp/us/cns/cns
    
    
18. 
    Hydrogen
    • (n.) A gaseous element, colorless, tasteless, and odorless, the lightest known substance, being fourteen and a half times lighter than air (hence its use in filling balloons), and over eleven thousand times lighter than water. It is very abundant, being an ingredient of water and of many other substances, especially those of animal or vegeta...
    Found on http://thinkexist.com/dictionary/meaning
    
    
19. 
    hydrogen
    a colourless, odourless, tasteless, flammable gaseous substance that is the simplest member of the family of chemical elements. The hydrogen atom has ... [102 related articles]
    Found on http://www.britannica.com/eb/a-z/h/88
    
    
20. 
    hydrogen
    hydrogen 1. A colorless, odorless, flammable gas that combines chemically with oxygen to form water: the lightest of the known chemical elements. 2. A colorless, highly flammable gaseous element, the lightest of all gases and the most abundant element in the universe, used in the production of synthetic ammonia and methanol, in petroleum refining, in th...
    Found on http://www.wordinfo.info/words/index/inf
    
    
21. 
    Hydrogen
    The element from which protons are extracted for acceleration.
    Found on http://www-bdnew.fnal.gov/operations/acc
    
    
22. 
    Hydrogen
    The element from which protons are extracted for acceleration.
    Found on http://www-bdnew.fnal.gov/operations/acc
    
    
23. 
    hydrogen
    Hydrogen diffusion flame in the Natural Gas Combustion Apparatus. Credit: National Energy Technology Laboratory A colorless, highly flammable, gaseous element. Hydrogen is the first and lightest element in the periodic table. It was first recognized as a distinct substance by Henry Cavendish in ...
    Found on http://www.daviddarling.info/encyclopedi
    
    
24. 
    hydrogen
    Hydrogen fuel cell A chemical element that can be used as an alternative fuel since it has a very high energy content. Hydrogen (H₂) will play an important role in developing sustainable transportation, because in the future it may be produced in virtually unlimited...
    Found on http://www.daviddarling.info/encyclopedi
    
    
25. 
    hydrogen
    hydrogen (hī'drujun) [Gr.,=water forming], gaseous chemical element; symbol H; at. no. 1; at. wt. 1.00794; m.p. -259.14°C; b.p. -252.87°C; density 0.08988 grams per liter at STP; valence usually +1.Sections in this article:IntroductionThe Isotopes and FormsPropertiesSources and Com...
    Found on http://www.infoplease.com/ce6/sci/A08247