What is chemistry?
Thanks to Dr. J. Stuart Grossert
Chemistry is a centuries-old science based on
observations and measurements. Chemists study the properties,
composition and structure of all forms of matter. In addition,
chemists study changes of matter when it interacts with other
matter or with different forms of energy; these changes enable
them to make new types of matter.
Matter is composed of some 103 elements, over 90 of which
are naturally occurring. Based on current knowledge, all matter
in our solar system is composed of the same elements. Elements
contain only one kind of atom, the smallest pieces of any element
that may exist.
All matter is composed of compounds, which in turn are composed
of two or more atoms, generally combined together in fixed ratios.
Any compound is a `chemical'.
Matter may be in the form of an invisible colourless gas,
such as oxygen, nitrogen or carbon dioxide. Matter may be a
heavy solid such as iron, a light solid such as a polystyrene
foam, a colourless, free-flowing liquid such as water, or a
viscous liquid mixture such as olive oil. Matter may be in the
form of very complex mixtures such as a sturdy piece of rock or
it may contain thousands of atoms in the form of a fragile
protein. Indeed, all living things are composed of a myriad of
complex chemicals, interacting with one another.
Since many types of matter are mixtures of many chemicals,
especially matter from natural sources, skilled chemical work is
essential to analyze such matter and determine what chemicals it
is composed of. At various concentrations, many chemicals are
toxic to different living species and therefore chemists perform
essential work not only by determining which chemicals are
present in a sample, but by analyzing how much of each chemical
Studying and handling different forms of matter is complex
because many systems are not static, but rather are dynamic; in
other words some chemicals may be converted into other chemicals
with time. This can happen because of the fact that 20% of the
earth's atmosphere is oxygen, which is a reactive chemical.
Classic reactions arising from oxygen are the spoiling of wine,
which is exposed to air or butter or olive oil, which turn
rancid after being in the air for too long. Other reactions
occur as a result of exposure of a chemical to sunlight, a
typical example being the yellowing of old paper or the fading
of dyes in a piece of coloured cloth. Chemists have been
studying such complex changes in chemical composition for
decades and many simpler cases are now understood. However,
modern developments continue with a remarkable pace and it is
now even possible that in some cases chemists can manipulate
individual atoms and molecules, concepts that could only be
dreamed of two decades ago.
Another key aspect of work by chemists is the conversion
of matter from one form into another, or of one chemical into
another. Many aspects of the world as we know it today are the
result of such work by chemists. For example, the formation of
light-weight metal alloys has made possible the building of the
airplanes, cars, trucks, trains and ships that allow goods and
people to move around the world. Other essentials of life today,
such as paper, glass, easy-care fabrics, computers, telephones
and televisions are all possible because of plastics or ultra pure
materials developed and characterized by chemists.