Structure and Function of Atoms and
Molecules Essential Ideas
Figure 1.1 Chemical substances and processes are essential for our existence, providing
sustenance, keeping us clean and healthy, fabricating electronic devices, enabling transportation,
and much more. (credit “left”: modification of work by “vxla”/Flickr; credit “left middle”: modification
of work by “the Italian voice”/Flickr; credit “right middle”: modification of work by Jason Trim; credit
“right”: modification of work by “gosheshe”/Flickr)
Introduction to Chemistry
Your alarm goes off and, after hitting “snooze” once or twice, you pry yourself out of bed. You
make a cup of coffee to help you get going, and then you shower, get dressed, eat breakfast, and
check your phone for messages. On your way to school, you stop to fill your car’s gas tank, almost
making you late for the first day of chemistry class. As you find a seat in the classroom, you read
the question projected on the screen: “Welcome to class! Why should we study chemistry?”
Do you have an answer? You may be studying chemistry because it fulfills an academic
requirement, but if you consider your daily activities, you might find chemistry interesting for other
reasons. Most everything you do and encounter during your day involves chemistry. Making coffee,
cooking eggs, and toasting bread involve chemistry. The products you use—like soap and shampoo,
the fabrics you wear, the electronics that keep you connected to your world, the gasoline that
propels your car—all of these and more involve chemical substances and processes. Whether you
are aware or not, chemistry is part of your everyday world. In this course, you will learn many of the
essential principles underlying the chemistry of modern-day life.
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1.1 Introduction to Chemistry and Measurement
By the end of this module, you will be able to:
• Outline the historical development of chemistry
• Provide examples of the importance of chemistry in everyday life
• Describe the scientific method
• Differentiate among hypotheses, theories, and laws
• Provide examples illustrating macroscopic, microscopic, and symbolic domains
Throughout human history, people have tried to convert matter into more useful forms. Our Stone
Age ancestors chipped pieces of flint into useful tools and carved wood into statues and toys. These
, endeavors involved changing the shape of a substance without changing the substance itself. But as
our knowledge increased, humans began to change the composition of the substances as well—clay
was converted into pottery, hides were cured to make garments, copper ores were transformed into
copper tools and weapons, and grain was made into bread.
Humans began to practice chemistry when they learned to control fire and use it to cook, make
pottery, and smelt metals. Subsequently, they began to separate and use specific components of
matter. A variety of drugs such as aloe, myrrh, and opium were isolated from plants. Dyes, such as
indigo and Tyrian purple, were extracted from plant and animal matter. Metals were combined to
form alloys—for example, copper and tin were mixed together to make bronze—and more
elaborate smelting techniques produced iron. Alkalis were extracted from ashes, and soaps were
prepared by combining these alkalis with fats. Alcohol was produced by fermentation and purified
by distillation.
Attempts to understand the behavior of matter extend back for more than 2500 years. As early as the
sixth century BC, Greek philosophers discussed a system in which water was the basis of all things.
You may have heard of the Greek postulate that matter consists of four elements: earth, air, fire,
and water. Subsequently, an amalgamation of chemical technologies and philosophical speculations
was spread from Egypt, China, and the eastern Mediterranean by alchemists, who endeavored to
transform “base metals” such as lead into “noble metals” like gold, and to create elixirs to cure
disease and extend life (Figure 1.2).
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Figure 1.2 This portrayal shows an alchemist’s workshop circa 1580. Although alchemy made
some useful contributions to how to manipulate matter, it was not scientific by modern
standards. (credit: Chemical Heritage Foundation)
From alchemy came the historical progressions that led to modern chemistry: the isolation of drugs
from natural sources, metallurgy, and the dye industry. Today, chemistry continues to deepen our
understanding and improve our ability to harness and control the behavior of matter.
, Chemistry: The Central Science
Chemistry is sometimes referred to as “the central science” due to its interconnectedness with a vast
array of other STEM disciplines (STEM stands for areas of study in the science, technology,
engineering, and math fields). Chemistry and the language of chemists play vital roles in biology,
medicine, materials science, forensics, environmental science, and many other fields (Figure 1.3).
The basic principles of physics are essential for understanding many aspects of chemistry, and there
is extensive overlap between many subdisciplines within the two fields, such as chemical physics
and nuclear chemistry. Mathematics, computer science, and information theory provide important
tools that help us calculate, interpret, describe, and generally make sense of the chemical world.
Biology and chemistry converge in biochemistry, which is crucial to understanding the many
complex factors and processes that keep living organisms (such as us) alive. Chemical engineering,
materials science, and nanotechnology combine chemical principles and empirical findings to
produce useful substances, ranging from gasoline to fabrics to electronics. Agriculture, food
science, veterinary science, and brewing and wine making help provide sustenance in the form of
food and drink to the world’s population. Medicine, pharmacology, biotechnology, and botany
identify and produce substances that help keep us healthy. Environmental science, geology,
oceanography, and atmospheric science incorporate many chemical ideas to help us better
understand and protect our physical world. Chemical ideas are used to help understand the universe
in astronomy and cosmology.
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Figure 1.3 Knowledge of chemistry is central to understanding a wide range of scientific
disciplines. This diagram shows just some of the interrelationships between chemistry and other
fields.
What are some changes in matter that are essential to daily life? Digesting and assimilating food,
synthesizing polymers that are used to make clothing, containers, cookware, and credit cards, and
refining crude oil into gasoline and other products are just a few examples. As you proceed through
this course, you will discover many different examples of changes in the composition and structure
of matter, how to classify these changes and how they occurred, their causes, the changes in energy
that accompany them, and the principles and laws involved. As you learn about these things, you
will be learning chemistry, the study of the composition, properties, and interactions of matter. The
practice of chemistry is not limited to chemistry books or laboratories: It happens whenever
someone is involved in changes in matter or in conditions that may lead to such changes.
, The Scientific Method
Chemistry is a science based on observation and experimentation. Doing chemistry involves
attempting to answer questions and explain observations in terms of the laws and theories of
chemistry, using procedures that are accepted by the scientific community. There is no single route
to answering a question or explaining an observation, but there is an aspect common to every
approach: Each uses knowledge based on experiments that can be reproduced to verify the results.
Some routes involve a hypothesis, a tentative explanation of observations that acts as a guide for
gathering and checking information. A hypothesis is tested by experimentation, calculation, and/or
comparison with the experiments of others and then refined as needed.
Some hypotheses are attempts to explain the behavior that is summarized in laws. The laws of
science summarize a vast number of experimental observations, and describe or predict some facet
of the natural world. If such a hypothesis turns out to be capable of explaining a large body of
experimental data, it can reach the status of a theory. Scientific theories are well-substantiated,
comprehensive, testable explanations of particular aspects of nature. Theories are accepted because
they provide satisfactory explanations, but they can be modified if new data become available. The
path of discovery that leads from question and observation to law or hypothesis to theory, combined
with experimental verification of the hypothesis and any necessary modification of the theory, is
called the scientific method (Figure
1.4).
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Figure 1.4 The scientific method follows a process similar to the one shown in this diagram. All the
key components are shown, in roughly the right order. Scientific progress is seldom neat and
clean: It requires open inquiry and the reworking of questions and ideas in response to findings.
The Domains of Chemistry
