The Foundations of Chemistry

We understand simple chemical systems well; they lie near chemistry’s fuzzy boundary

with physics. They can often be described exactly by mathematical equations. We fare less

well with more complicated systems. Even where our understanding is fairly thorough,

we must make approximations, and often our knowledge is far from complete. Each year

researchers provide new insights into the nature of matter and its interactions. As chemists

find answers to old questions, they learn to ask new ones. Our scientific knowledge has

been described as an expanding sphere that, as it grows, encounters an ever-enlarging

frontier.

In our search for understanding, we eventually must ask fundamental questions, such

as the following:

Howdo substances combine to form other substances? How much energy is involved

in changes that we observe?

Howis matter constructed in its intimate detail? How are atoms and the ways that they

combine related to the properties of the matter that we can measure, such as color,

hardness, chemical reactivity, and electrical conductivity?

Whatfundamental factors influence the stability of a substance? How can we force a

desired (but energetically unfavorable) change to take place? What factors control the

rate at which a chemical change takes place?

In your study of chemistry, you will learn about these and many other basic ideas that

chemists have developed to help them describe and understand the behavior of matter.

Along the way, we hope that you come to appreciate the development of this science, one

of the grandest intellectual achievements of human endeavor. You will also learn how to

apply these fundamental principles to solve real problems. One of your major goals in the

study of chemistry should be to develop your ability to think critically and to solve prob-

lems (not just do numerical calculations!). In other words, you need to learn to manipu-

late not only numbers, but also quantitative ideas, words, and concepts.

In the first chapter, our main goals are (1) to begin to get an idea of what chemistry is

about and the ways in which chemists view and describe the material world and (2) to

acquire some skills that are useful and necessary in the understanding of chemistry, its

contribution to science and engineering, and its role in our daily lives.

MATTER AND ENERGY

Matteris anything that has mass and occupies space. Mass is a measure of the quantity

of matter in a sample of any material. The more massive an object is, the more force is

required to put it in motion. All bodies consist of matter. Our senses of sight and touch

usually tell us that an object occupies space. In the case of colorless, odorless, tasteless

gases (such as air), our senses may fail us.

Energyis defined as the capacity to do work or to transfer heat. We are familiar with

many forms of energy, including mechanical energy, light energy, electrical energy, and

heat energy. Light energy from the sun is used by plants as they grow, electrical energy

allows us to light a room by flicking a switch, and heat energy cooks our food and warms

our homes. Energy can be classified into two principal types: kinetic energy and poten-

tial energy.

A body in motion, such as a rolling boulder, possesses energy because of its motion.

Such energy is called kinetic energy.Kinetic energy represents the capacity for doing

work directly. It is easily transferred between objects. Potential energyis the energy an

1-

We might say that we can “touch” air
when it blows in our faces, but we
depend on other evidence to show that
a still body of air fits our definition of
matter.

The term comes from the Greek word
kinein,meaning “to move.” The word
“cinema” is derived from the same
Greek word.

4 CHAPTER 1: The Foundations of Chemistry