7.1 Overview of Molecules and Matter

At this juncture, the reader should be comfortable with a range of basic ideas such as symmetry, light, the electrostatic force, and atoms and molecules that are essential to understanding the laptop computer and life. However, the discussion has not dealt with macroscopic objects that contain large numbers of molecules. We are finally in a position to rectify this omission. This chapter will begin by reminding you that in your experiences with matter you almost always deal with a very large number of molecules. Thus, our discussion must evolve and begin to focus on the behavior of a large number of molecules acting as a group. The present discussion will be limited to (essentially) standard solids, liquids and gases. In later chapters the discussion will focus on the specific types of materials that are important in laptops and life.

This chapter will answer the following questions.

1. What physical variables determine how molecules interact and the properties of the resulting phase of the material?

2. What kinds of arrangements of atoms are observed?

3. A set of related questions: What is heat? What is thermal energy? What is temperature? How do these quantities affect the arrangement of molecules?

4. How do we characterize the properties of the various phases of matter? Are there any general rules that describe this behavior?

5. What are the characteristics of the common phases of matter?

7.2 Introduction

So far we have discussed individual atoms or a relatively few atoms that combined to...