Introduction

You've passed the first hurdle in understanding a little about chemistry: You've picked up Chemistry For Dummies, 2nd Edition. I imagine that a large number of people looked at the title, saw the word chemistry, and bypassed it like it was covered in germs.

I don't know how many times I've been on vacation, struck up a conversation with someone, and been asked the dreaded question: "What do you do?"

"I'm a teacher," I reply.

"Really? And what do you teach?"

I steel myself, grit my teeth, and say in my most pleasant voice, "Chemistry."

I see The Expression, followed by, "Oh, I never took chemistry. It was too hard." Or "You must be smart to teach chemistry." Or "Goodbye!" If I were still in the dating scene, "Hi, I teach chemistry" would not be a good pick-up line!

I think a lot of people feel this way because they think that chemistry is too abstract, too mathematical, too removed from their real lives. But in one way or another, all of us do chemistry.

Remember making that baking soda and vinegar volcano as a child? That's chemistry. Do you cook or clean or use fingernail polish remover? All that is chemistry. I never had a chemistry set as a child, but I always loved science. My high school chemistry teacher was a great biology teacher but really didn't know much chemistry. But when I took my first chemistry course in college, the labs hooked me. I enjoyed seeing the colors of the solids coming out of solutions. I enjoyed synthesis, making new compounds. The idea of making something nobody else had ever made before fascinated me. I wanted to work for a chemical company, doing research, but then I discovered my second love: teaching.

Chemistry is sometimes called the central science (mostly by chemists), because in order to have a good understanding of biology or geology or even physics, you must have a good understanding of chemistry. Ours is a chemical world, and I hope that you enjoy discovering the chemical nature of it - and that afterward, you won't find the word chemistry so frightening.

About This Book

My goal with this book is not to make you into a chemistry major. My goal is simply to give you a basic understanding of some chemical topics that commonly appear in high school or college introductory chemistry courses. If you're taking a course, use this book as a reference in conjunction with your notes and textbook.

Simply watching people play tennis, no matter how intently you watch them, will not make you a tennis star. You need to practice. And the same is true with chemistry. It's not a spectator sport. If you're taking a chemistry course, then you need to practice and work on problems. I show you how to work certain types of problems - gas laws, for example - but use your textbook for practice problems. It's work, yes, but it really can be fun.

As I updated this second edition of Chemistry For Dummies, I reflected on what to include. I've enjoyed getting e-mails from people all over the world asking questions about the first edition or thanking me. However, looking at the overall feedback, I felt that I hadn't included quite enough about calculations and some other topics that students taking a college or high school-level class really needed. So in this second edition I beefed up the calculations and included some extra topics normally found in the first year of high school chemistry or the first semester of general chemistry in college. Overall, this edition will be more useful to those of you taking the chemistry course. For those of you who want some help with second-semester topics, hang in there and maybe, just maybe, you'll soon see Chemistry II For Dummies in your local bookstore.

Foolish Assumptions

I really don't know why you bought this book (or will buy it - in fact, if you're still in the bookstore and haven't bought it yet, buy two and give one as a gift), but I assume that you're taking (or retaking) a chemistry course or preparing to take a chemistry course. I also assume that you feel relatively comfortable with arithmetic and know enough algebra to solve for a single unknown in an equation. And I assume that you have a scientific calculator capable of doing exponents and logarithms.

And if you're buying this book just for the thrill of finding out about something different - with no plan of ever taking a chemistry course - I applaud you and hope that you enjoy this adventure. Feel free to skip those topics that don't hold your interest; for you, there will be no tests, only the thrill of increasing your knowledge about something new.

What Not to Read

I know you're a busy person and want to get just what you need from this book. Although I want you to read every single word I've written, I understand you may be on a time crunch. I keep the material to the bare bones, but I include a few sidebars. They're interesting reading (again, at least to me) but not really necessary for understanding the topic at hand, so feel free to skip them. This is your book; use it any way you want.

I mark some paragraphs with Technical Stuff icons. What I tell you in these paragraphs is more than you need to know, strictly speaking, but it may give you helpful or interesting detail about the topic at hand. If you want just the facts, you can skip these paragraphs.

How This Book Is Organized

I present this book's content in a logical progression of topics. But this doesn't mean you have to start at the beginning and read to the end of the book. Each chapter is self-contained, so feel free to skip around. Sometimes, though, you'll get a better understanding if you do a quick scan of a background section as you're reading. To help you find appropriate background sections, I've placed "see Chapter X for more information" cross-references here and there throughout the book.

Because I'm a firm believer in concrete examples, I also include lots of illustrations and figures with the text. They really help in the understanding of chemistry topics. And to help you with the math, I break up problems into steps so that you can easily follow exactly what I'm doing.

I've organized the topics in a logical progression - basically the same way I organize my courses for science and non-science majors. Following is an overview of each part of the book.

Part 1: The Basic Concepts of Chemistry

In this part, I introduce you to the really basic concepts of chemistry. I define chemistry and show you where it fits among the other sciences (in the center, naturally). I show you the chemical world around you and explain why chemistry should be important to you. I also have a chapter (Chapter 2) devoted to chemical calculations. I show you how to use the factor label method of calculations, along with an introduction to the SI (metric) system. I also show you the three states of matter and talk about going from one state to another - and the energy changes that occur.

Besides covering the macroscopic world of things like melting ice, I cover the microscopic world of atoms. I explain the particles that make up the atom - protons, neutrons, and electrons - and show you where they're located in the atom.

I discuss how to use the periodic table, an indispensable tool for chemists. And I introduce you to the atomic nucleus, including the different subatomic particles. Finally, I introduce you to the wonderful world of gases. In fact, in the gas chapter, you can see so many gas laws (Boyle's law, Charles's law, Gay-Lussac's law, the combined gas law, the ideal gas law, Avogadro's law, and more) that you may feel like a lawyer when you're done. The material in these chapters gets you ready for additional topics in chemistry.

Part 2: A Cornucopia of Chemical Concepts

In this part, you get into some really good stuff: chemical reactions. I give some examples of the different kinds of chemical reactions you may encounter and show you how to balance them. (You really didn't think I could resist that, did you?) I also introduce the mole concept. Odd name, yes, but the mole is central to your understanding of chemical calculations. It enables you to figure the amount of reactants needed in chemical reactions and the amount of product formed. I also talk about solutions and how to calculate their concentrations. And I explain why I leave the antifreeze in my radiator during the summer and why I add rock salt to the ice when I'm making ice cream.

This part gets into thermochemistry. Energy changes take place during chemical reactions. Some reactions give off energy (mostly in the form of heat), and some absorb energy in the form of heat. I show you how to figure how much heat is released. It may be enough to make you break out in a sweat. Finally, I tell you about acids and bases, things sour and things bitter. I discuss how to calculate their concentration and the pH of a solution.

Part 3: Blessed Be the Bonds That Tie

I start off in this part talking about quantum theory, through which an electron can be represented by the properties of both particles and waves. In the first chapter, I throw...