Hydrogen makes up 98% of the known universe,
and it is the third most abundant element on the earth's
surface.It is the lightest of all the
gases, with a gaseous specific gravity of 0.0695. It is a
component of water, minerals and acids, and it makes up a
fundamental part of all hydrocarbons and organic substances. At
atmospheric temperatures and pressures, hydrogen exists as a
gas; however, it liquefies at -252.9°C (-423°F). Next to helium,
it is the coldest known fluid.
Hydrogen is one of the
materials now being considered as an alternative fuel because it
is renewable, abundant, efficient, and unlike other
alternatives, produces zero emissions. Many believe that this
versatile material will become a primary fuel and energy carrier
of the future.
