http://www.ck12.org Chapter 1. Introduction to Chemistry
chemists at DuPont were searching for a new lightweight and strong fiber that could be used in tires. Chemist
Stephanie Kwolek discovered, somewhat by accident, that a certain solution she had made displayed unique charac-
teristics that were unlike those of other previously developed substances. The rapid expansion in the field of polymer
chemistry that has occurred over the past 50 years was partially due to the results of her research. Polymers are very,
very large molecules comprised of smaller subunits that are repeated over and over again in extremely long chains.
The polymer that was discovered at DuPont was eventually given the name Kevlar. It is used not only in tires but
also in bulletproof body armor because of its high strength and light weight. Polymer chemistry continues to be an
active and vibrant field of chemistry, as both a pure and an applied discipline.
Chemistry Disciplines
The study of modern chemistry has many, many branches, but it can generally be broken down into five main
disciplines, or areas of study. Physical chemistryis the study of both macroscopic and atomic properties and
phenomena in chemical systems. A physical chemist may study such things as the rates of chemical reactions, the
energy transfers that occur during a reaction, or the physical structure of materials at the molecular level.Organic
chemistryis the study of carbon-containing chemicals. Carbon is one of the most abundant elements on Earth and is
capable of forming a tremendously vast number of chemicals. Most of the chemicals found in living organisms are
based on carbon.Inorganic chemistryis the study of chemicals that do not, in general, contain carbon. Inorganic
chemicals are commonly found in rocks and minerals. Analytical chemistryis the study of the composition of
matter, with a focus on separating, identifying, and quantifying chemical samples. An analytical chemist may use
complex instruments to analyze an unknown material in order to determine its various components (Figure1.3).
Biochemistryis the study of chemical processes that occur in living things. Due to the importance of carbon-
containing compounds in living organisms, biochemistry and organic chemistry are often closely interrelated.
In practice, chemical research is often not limited to just one of the five major disciplines. For example, a chemist
might use biochemistry techniques to isolate a particular chemical from the human body, such as hemoglobin, the
oxygen-carrying component of red blood cells. He or she may then proceed to analyze the hemoglobin using methods
that would pertain to physical or analytical chemistry. Many chemists specialize in areas that are combinations of
these primary disciplines, such as bioinorganic chemistry or physical organic chemistry.
Chemistry in the World Today
Chemistry has played and will continue to play a central role in all areas of science and technology. Before delving
into the specifics of chemistry, it is worthwhile to examine a few of the frontiers that chemists are currently exploring
and to review how chemistry has helped shape these fields.
Energy
Virtually all chemical reactions involve a transfer of energy, and the worldwide demand for energy continues to
increase every year. The majority of our energy needs since the Industrial Revolution have been met by the burning
of fossil fuels. Fossil fuels (coal, petroleum, natural gas) were formed millions of years ago from the remains
of plants and animals. Fossil fuels are a nonrenewable energy source, meaning that they cannot be produced or
regenerated, so the global supply will eventually be exhausted. Chemists are actively involved in finding ways to
conserve energy and to utilize alternative energy sources.
Nuclear energy is obtained by splitting large atoms such as uranium into smaller atoms in a process called nuclear
fission. Nuclear fission releases tremendous amounts of energy, much more than burning an equivalent amount of
fossil fuels. While nuclear energy is widely used to supplement the energy demands of modern society, it comes
with risks and drawbacks. For example, nuclear power generates waste that is dangerously radioactive and difficult