Preface

This course on college chemistry provides a way for the college student pursuing an interest in chemistry or possibly already struggling with chemistry to understand this discipline in a much clearer way. Chemistry is a broad subject, ranging from “physical chemistry” or the study of atoms, molecules, chemical reactions, and the properties of solids, liquids, and gases, to things like “organic chemistry” and “biochemistry” that deal with the topic of the chemistry specific to carbon-based molecules, which are the molecules of living things.

In some ways, the majority of chemistry is about the physical properties of atoms and molecules in singular form as well as the physical properties of molecules in different states, including the molecular properties of gases, solids, and liquids. Most atoms and molecules are not inert and interact with one another in specific ways. This will be a major focus in this course as we learn about how different substances exist in natural and experimental situations.

Chapter one in the course introduces chemistry in its most basic form by covering atoms and their nature. Everything in the universe is made from different types of atoms. As it turns out, atoms have specific sub-particles that make up the basic structure of the atom. There are also numerous different atoms in nature, as we’ll discuss when talking about the periodic table, which outlines the relationships between different types of atoms. Finally, there is a discussion on the concept of the “mole” as it exists in understanding quantities of atoms and molecules.

The focus of chapter two is the structure of atoms. As it turns out, there are specific rules that define how subatomic structures are organized. This chapter will cover the arrangement of electrons, and both the Pauli principle and Aufbau Principle, which define electron relationships inside the atom. Electrons have a natural affinity for the proton they surround but also allow for affinity of different types of atoms in the formation of larger molecules. This will be discussed in this chapter.

The main topics of chapter three in the course are the properties of gases. There are specific laws that describe the behavior of gases in chemistry, which are covered in this chapter. The study of gases involves the relationship between volume and pressure in a gas and, in the situation of mixed gases, a relationship between the different gases in a given volume. The behavior of gases in relation to the ideal gas law is covered in this chapter as well as the study of the kinetics of gas molecules in a gaseous solution.

Chapter four discusses chemistry as it relates to heat, also called “thermochemistry”. There is an intricate connection between molecules and the temperature of the atoms in the molecules. Concepts of heat capacity and calorimetry are discussed as they relate to a specific molecule. The enthalpy or the total heat in a given system is discussed as it relates to the energy of the system. As in all of physical chemistry, there are specific rules related to the properties of substances at different temperatures, which are covered in this chapter.

Chapter five in the course gets into the subject of chemical bonding and molecular structure. Unless an atom is completely inert, it will have the natural tendency to interact with other atoms. This is certainly the case with ionic substances in chemistry. The chapter will study the important topic of covalence and covalent bonding between molecules and how this should look from an atomic perspective. Because of the different properties of atoms, they exist within molecules in specific three-dimensional arrangements, which is covered in this chapter. The topic of bonding in metallic atoms is also covered as part of this chapter.

Chapter six focuses on the inevitability of chemical reactions and on what chemical formulas look like. Molecules and atomic substances tend not to stay separate from one another when put together in the same physical space and reactions will follow a specific pattern. The rates of different reactions and why they occur or do not occur are discussed as well as the issue of the energy of activation necessary to take a group of molecules in one form and turn them into molecules of a different form. Exactly what happens in chemical reactions is covered as part of this chapter.

The focus of chapter seven in the course is the behavior of solids and liquids. Molecules can exist in crystalline form, depending on the physical circumstances. There are certain

molecular forces in play when substances are in crystalline form, which are discussed in this chapter. In the same way, liquids have certain properties unique to that state that depend on the atomic nature of the molecule and on the temperature of the liquid. The different forces in play when substances are in liquid form are covered in the chapter.

The study of liquids continues in chapter eight with a discussion of solutions and colloids. Solutions involve the dissolution of a substance in a liquid medium. Exactly how this is successfully done is covered as part of this chapter as well as what it means to indicate the “concentration” of a solute in solution. A solution is a unique medium for reactions to take place, as it exhibits certain properties that keep things in a given solution and that help drive reactions within the solution. Colloids have certain properties that will also be discussed.

Two significant types of reactions are covered in chapter nine in the course—that being oxidation and reduction reactions, which are opposing but interrelated chemical reactions. Because these reactions happen in a balanced way, they are often discussed together. Taken together, an oxidation-reduction reaction is any chemical reaction in which the oxidation number of a molecule, atom, or ion is altered by gaining or losing an electron.

The specific properties of acids and bases are discussed in chapter ten in the course. Methods involved in the titration of acids and bases are discussed as part of this chapter as are properties of strong and weak acids and bases. Buffers are weak acids or weak bases that prevent significant changes in the pH of a solution; how these substances work in acid-base chemistry is covered. Finally, the action of hydrolysis is an important part of the discussion in this section.

The focus of chapter eleven in the course is electrochemistry, or the study of electricity as it applies to chemical reactions. Faraday’s law, which states that the amount of substance produced at an electrode is directly proportional to the quantity of charge flowing through an electrochemical cell, is discussed. The basics of electricity in chemical reactions are important to understand because electricity plays a role in many chemical interactions. The different properties of electrical cells and what makes them up is a part of this chapter’s discussion.

Organic chemistry and biochemistry are courses of their own; however, they are covered together in chapter twelve in the course because they are inter-related and important aspects of the study of chemistry. Organic chemistry is carbon-based chemistry and involves a variety of different types of molecules and reactions typically seen in living things. The nature of organic molecules is discussed as well as the functional groups that shape organic molecules and their behavior. Finally, biochemistry and its principles are covered as these types of molecules, too, follow the basic chemical principles already laid out in this course.