smelting A process using high temperatures that
separates a pure metal, usually in a molten form, from
an ore.
smog A noxious mixture of air pollutants including
gases and fine particles that can often be seen as a
brownish-yellow or greyish-white haze.
See alsoPHOTOCHEMICAL SMOG.
SN1/SN2 reactions Substitution reactions (SN1/SN2).
There are two basic kinds of substitution reactions:
SN2 = substitution nucleophilic bimolecular
SN1 = substitution nucleophilic unimolecularA NUCLEOPHILEis an electron-rich species that will
react with an electron-poor species. A substitution
implies that one group replaces another, with the for-
mation of a new bond to the nucleophile and the
breaking of a bond to the leaving group.
soap A material used for cleaning made from the salts
of vegetable or animal fats. The chemical reaction that
makes soap and glycerin from fatty acids and sodium or
potassium hydroxide is called SAPONIFICATION.
SOD SeeSUPEROXIDE DISMUTASE.
Soddy, Frederick (1877–1956) British Physicist
Frederick Soddy was born at Eastbourne, Sussex, En-
gland, on September 2, 1877, to Benjamin Soddy, a
London merchant. He was educated at Eastbourne Col-
lege and the University College of Wales, Aberystwyth.
After receiving a scholarship at Merton College,
Oxford, in 1895, he graduated three years later with
first-class honors in chemistry. After spending two
years doing research at Oxford, he moved to Canada,
and during 1900–02 he was demonstrator in the chem-
istry department of McGill University, Montreal, work-
ing with ERNESTRUTHERFORDon the problems of
radioactivity. He married Winifred Beilby in 1908.
From 1904 to 1914 he was a lecturer in physical chem-
istry and radioactivity at the University of Glasgow,
and after teaching in Scotland, he was appointed pro-
fessor of chemistry at Oxford (1919–36).
He was one of the first to conclude in 1912 that
some elements can exist in forms that “are chemically
identical, and save only as regards the relatively few
physical properties which depend on atomic mass
directly, physically identical also.” He called them iso-
topes. Later he promoted their use in determining geo-
logic age. He is credited (with others) with the
discovery of the element protactinium in 1917.
In 1921 he was awarded the Nobel Prize in chem-
istry “for his contributions to our knowledge of the
chemistry of radioactive substances, and his investiga-
tions into the origin and nature of isotopes.”
He published several books, including: Radioactivity
(1904), The Interpretation of Radium (1909), The248 smelting
The Role of Chemistry
by Karl F. Moschner, Ph.D.
Chemistry—the science of the properties, composition,
structure, and reactions of substances—has always been
an integral part of mankind’s everyday life. Long before
chemistry was a recognized field of science and even
before recorded history, chemistry yielded numerous useful
discoveries to inquisitive minds. Even common materials
and everyday activities offer opportunities for new discov-
eries and a deeper understanding of the chemical pro-
cesses that impact our lives and the world around us.
Nothing dramatizes this point more than the use of
fire, one of the four ancient elements, the others being air,earth, and water. In Greek mythology, Prometheus stole
fire from the gods and gave it to mankind. While fire pre-
sented many dangers, over thousands of years it provided
mankind with light, warmth, and numerous other benefits.
Even the by-products of incomplete combustion such as
charcoal and carbon black found uses. Yet it was not until
the 1980s that modern chemists discovered that soot, from
combustion of organic matter, contained a symmetrical,
soccer-ball-shaped molecule composed of 60 carbon
atoms, named buckminsterfullerene in honor of the archi-
tect Buckminster Fuller, a leading proponent of the
geodesic dome that it resembled. The serendipitous dis-
covery of this ancient and ubiquitous third allotrope of the
element carbon led to an explosion in new research with(continued on p. 250)