Download Glossary of Terms Used in Articles about the Hydrogen Economy at

Glossary of Terms Used in Articles about the Hydrogen Economy
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Biomass
Plant material, vegetation, or agricultural waste used as a fuel or energy source.
Bond
Sometimes called a chemical bond, an attractive force between atoms strong enough
to allow the resulting element to function as a unit.
By-product
Commonly known as something that is made as a result of producing something else. It
is a secondary result or effect. Hydrogen can be made as a result of nuclear fission or
petroleum refining. The primary task is creating the nuclear power or oil for fuel, but
hydrogen is made as a secondary result.
Electrolysis
Using electricity to split molecules, such as water, into positive and negative ions
(hydrogen and oxygen ions). The ions that are collected can be collected or released.
Electron
A fundamental particle of matter, an electron can exists as a component of an atom or in
the free state. Each electron carries one unit of negative charge and has a very small
mass as compared with that of a neutron or proton.
Fuel reforming
Reforming is decomposition (cracking) of hydrocarbon gases or petroleum-based
products by heat and pressure. Some processes use a catalyst to make the reforming
more efficient. Steam reforming of natural gas is a way to produce hydrogen.
A catalyst is an element that helps a chemical reaction happen without itself being
changed. Iron oxidizes naturally in the air, but is hastened when water vapor is added.
The water vapor is the catalyst.
Hydrogen
The most abundant element in the universe, it consists of one proton in the nucleus and
one electron in one shell. It is the lightest and most simple element.
Infrastructure
The basic facilities and services needed for the functioning of a community or society,
such as transportation and communications systems, water and power lines, and public
institutions including schools, post offices, and prisons.
In the case of hydrogen fuel cells, the infrastructure is the underlying system to deliver
hydrogen fuel for safe and efficient refueling. This may mean hydrogen refueling stations
like today’s gas stations.
Ion
An atom that has lost or gained one or more electrons, and now has an electric charge.
Positively charged ions are cations, while negatively charged ions are anions. An ion
often has entirely different properties from the element or atom from which it was
formed.
Neutron
A component of an atomic nucleus with a mass of 1.009 and carries no electrical charge
(neutral). It is a part of the nucleus of all elements except hydrogen. The number of
neutrons in the nucleus causes the difference between the atomic number and the
atomic mass of an element.
Nucleus
The positively charged central mass of an atom, it contains essentially the total mass,
which is calculated by adding the number of protons to the number of neutrons.
Periodic Table
A specific arrangement of chemical elements, the Periodic Table groups elements
according to periodic law. This grouping places atoms that have the same number of
electrons in the outer shell in the same “period.” Then, all elements are arranged by
increasing atomic number, creating groups that are meaningful to scientists.
R. T. Sanderson submitted a modern definition of periodic law: The electronic
configurations of the atoms of the elements vary periodically with their atomic number.
Consequently all properties of the elements that depend on their atomic structure
(electronic configuration) tend also to change with increasing atomic number in a
periodic manner.
Source: Hawley’s Condensed Chemical Dictionary, Eleventh Edition; Revised by N. Irving Sax and
Richard J. Lewis, Sr. Copyright 1987, Van Nostrand Reinhold Company, Inc.
Proton
A component of an atomic nucleus with a mass defined as 1 and carries one unit of
positive charge. The nucleus of a hydrogen atom contains only one proton.
Renewable
Replaceable. For energy, this means that we can make more of it. Fossil fuels are not
renewable because once they are used they are gone. Energy that comes from wind,
water, sun or biomass is renewable because the sources are not used up in the process
of making energy.
Shell
In physical chemistry, this term refers to any of the paths or orbits of electrons in an
atom as they revolve around its nucleus. There may be from one to seven shells. The
number of electrons and number of shells helps place elements on the Periodic Table.
The laws of physics limit the number of electrons in the shells: two in the first shell, eight
in the second, 18 in the third, and 32 in the fourth.
This glossary was created with the assistance of the following source: Hawley’s Condensed Chemical
Dictionary, Eleventh Edition; Revised by N. Irving Sax and Richard J. Lewis, Sr. Copyright 1987, Van
Nostrand Reinhold Company, Inc.