Chemistry II For Dummies^®

Introduction

Congratulations. You jumped the first hurdle in understanding the basics of chemistry by passing Chemistry I. Perhaps you even used my book, Chemistry For Dummies, Second Edition (John Wiley & Sons, Inc.). If you did, thank you. If you didn’t, I’m glad you’ve entrusted me with your Chemistry II endeavors. The very fact that you’re at least looking at this book indicates that you feel you may need a little help in your Chemistry II class. Chem I (believe it or not) isn’t as mathematical as Chem II. In Chem I you had a lot of descriptive material; Chem II is all about solving problems, so get ready.

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 the second half of a university introductory chemistry course or the second year in a high school chemistry course. If you’re taking a course, use this book as a reference in conjunction with your notes and textbook.

Simply watching people play the piano, no matter how intently you watch them, doesn’t make you a musical expert. You need to practice. And the same is true with chemistry. It’s not a spectator sport. You probably figured that out in Chem I; you need to practice and work on problems. Chemistry II adds a lot more math problems, which may be challenging for some people. Sharpen up your calculator skills — you’ll need them. I show you how to work certain types of problems in this book — homogeneous equilibrium, for example — but use your textbook for practice problems. It’s work, yes, but it really can be fun. This book is for those of you who want some additional help with Chem II topics.

Foolish Assumptions

When I wrote this book, I made a few assumptions about you. Those assumptions include the following:

You’re taking (or retaking) a second-semester college chemistry course or preparing to take a second-semester college chemistry course.

You’re taking (or retaking) a second-year high school chemistry course or preparing to take a second-year high school chemistry course.

You at least passed the first-year high school chemistry course and are wondering whether you want to take the next class.

You at least passed the first-semester college chemistry course and are wondering whether you want to take the next class.

You feel relatively comfortable with arithmetic and know enough algebra to solve for a single unknown in an equation.

You have a scientific calculator capable of doing exponents and logarithms.

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. If so, feel free to skip the sidebars, the gray-shaded boxes that appear here and there. These interesting bits of info aren’t essential to understanding the stuff you need to know.

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

Part I: A Basic Review of Chemistry I

In this part, I give you a basic review of those topics commonly found in a Chem I course that I feel are critical to your progression through the Chem II concepts. I review the simple concepts of chemistry in Chapter 1, and then in Chapter 2, I give you a quick review of chemical calculations. I show you how to use the factor label method of calculations, along with an introduction to the SI (metric) system.

In Chapter 3, I give a review of atomic structure, the periodic table, and the different types of bonding. I don’t cover topics in a lot of depth, but just enough to jog your memory about energy level configurations, periodicity, and bonding. In Chapter 4, I give you a good review of reaction stoichiometry because you will really need these mole-related concepts in Chem II.

In Chapter 5, I review solutions and solution concentration units. I also review the different types of intermolecular forces and the properties of liquids. In Chapter 6, I review the properties of gases including the 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’s it! Six chapters of review of a course it took half a year (or a full year) to complete.

Part II: Diving Into Kinetics and Equilibrium

In this part, you get into the real meat of Chemistry II. In Chapter 7, I discuss the factors associated with the speed of a reaction. I show you how to determine the rate law for a reaction. A rate law relates the changes in concentrations of reactants to the overall speed of reaction. I also discuss the current model on how reactions occur and end up with a discussion of catalysts.

The rest of this part focuses on equilibrium — three chapters worth. The study of equilibrium is probably the most important topic in a second-semester college chemistry (or a second-year high school) course. First, I introduce you to the basic concepts of equilibriums, and then I apply these basic concepts to homogeneous equilibrium systems. I also cover acid-base equilibrium systems, heterogeneous equilibrium systems (solubility), and complex ion equilibrium. Lots of different types of equilibriums, yet all remarkably similar.

Part III: A Plethora of Chemistry II Concepts

In this part I start off by examining thermodynamics, building on that little taste of thermochemistry you studied in Chem I. I talk about enthalpy and entropy and Gibbs Free Energy, as well as the three laws of thermodynamics. Then it’s off to electrochemistry for a discussion of redox reactions. I show you how to balance redox reactions, which can be a bane of second-semester chemistry students, and then show how redox reactions are related to electrochemical cells — batteries and electroplating.

The last three chapters of this part give you a rest from calculations. I start off by giving you a glimpse into the world of organic chemistry, the chemistry of carbon. I discuss hydrocarbons in a little detail and give you a brief introduction to other functional groups, such as the alcohols. Then I show you an application of organic chemistry — polymers. I discuss some of the different types of polymers (plastics) in terms of their structure and usage. Finally, I introduce you to the world of biochemistry, the chemistry of living things.

Part IV: Describing Descriptive Chemistry

In this part, I start by discussing the chemistry of petroleum. I introduce terms like cracking and reforming around, as well as discussing what that octane rating really means. Then I leave an old fuel for a new fuel — nuclear power. I show you the different types of nuclear decays, discuss fission and fusion, and show how to deal with half-life problems.

I finish up this part, with a discussion of chemistry in the home. That’s not covered much in general chemistry, but I believe that you deserve an opportunity to explore the practical side of chemistry a little. I discuss the chemical nature of soaps and detergents, deodorants and antiperspirants, aspirin and Viagra.

Part V: The Part of Tens

In this part, I introduce you to ten terrific tips for passing Chem II. They really do work. Then I give you the top ten mathematical formulas that you will be using in Chem II, and wind up with ten chemical careers, for those of you who are dreaming about graduating and getting a job in chemistry.

Icons Used in This Book

If you’ve read other For Dummies books, you recognize the icons used in this book, but here’s the quickie lowdown for those of you who aren’t familiar with them:

This icon gives you a tip on the quickest, easiest way to perform a task or conquer a concept. This icon highlights stuff that’s good to know and stuff that’ll save you time and/or frustration.

The Remember icon is a memory jog for those really important things you shouldn’t forget.

I use this icon when I describe safety in doing a particular activity, especially mixing chemicals.

This icon points out different example problems you may encounter with the respective topic. I walk you through them step by step to help you gain confidence.

I don’t use this icon very often because I keep the content pretty basic. But in those cases where I expand on a topic beyond the basics, I use this icon. You can safely skip this material, but you may want to look at it if you’re interested in a more in-depth description.

Where to Go from Here

I present this book’s content in a logical (at least to me) 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 XX 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.

If you’re trying to clarify something specific, go right to that chapter and section. If you’re a real novice, start with Chapter 1 and go from there. If you did okay in Chemistry I, I suggest quickly reviewing Part I and then going on to Part II. Chapter 7 on kinetics is essential, and so are Chapters 8–10 on equilibrium.

You really can’t go wrong. Whether taking a course, reviewing for a professional exam, or just wanting to know a little more about chemistry, I think you will get your money’s worth. I hope that you enjoy your chemistry trip.

Chapter 1

I Passed Chem I, But What About Chem II?

In This Chapter

Comprehending chemistry

Discovering science and technology

Examining the general areas of chemistry

You already know what chemistry is. You passed your first year of high school or your first semester of college chemistry. Now you’re ready to take on your second year or second semester, and you want a resource to help you explain concepts in plain English. This chapter sets the stage for the rest of the book by showing you what the differences are between Chem I and Chem II so that you can relate better to this new material. It also relates some of the major areas of chemistry to the topics you’ll be studying in Chemistry II. If you’re already in the midst of a Chem II college or high school course, you may want to skim over this chapter for a quick review of some basic concepts and then go right to the subject area in the book that is troubling you.

If you bought this book just to have fun discovering something new and aren’t taking a chemistry course, you may need a little refresher on the really fundamental chemical topics. I suggest buying a copy of the first book in this series, Chemistry For Dummies. That book, now in its second edition, can give you the basics and make this book more meaningful.

Teaching chemistry is very enjoyable. For me, it’s more than just a collection of facts and a body of knowledge. Although I wasn’t a chemistry major when I entered college, I quickly became hooked when I took my first chemistry course. The subject seemed so interesting and so logical. Watching chemical changes take place, figuring out unknowns, using instruments, extending my senses, and making predictions to figure out why they were right and wrong all seems so fascinating. Your journey into Chem II starts here.

Grasping the Nature of Chemistry II

Chem I, in most schools, is a mixture of a lot of different topics. You naturally find some carryover between topics; you finish the chapter on gases and only briefly cover those topics again, until you hit the final exam. Your Chemistry II class is more consistent in these topics. Chem II is also much more mathematical than Chem I, which was great for me because I always enjoyed the quantitative aspects of chemistry more than the descriptive part. That’s why I am an analytical chemist instead of an organic chemist. I enjoy working with numbers.

The following sections give you a quick reminder at the content in a typical Chem I course and then show you what to expect in a typical Chem II class that you are or might be taking.

Recapping general Chemistry I

In your first couple of weeks in your Chemistry II class, you probably will review the basics of what you covered in your Chemistry I class. I dedicate the chapters in Part I of Chemistry II For Dummies to these topics to help you review these important topics. Here are the topics you can find:

Problem solving: The metric or SI system is essential to studying chemistry at any level. You need to be able to use the factor-label method of problem solving, also called unit analysis. This method allows you to manipulate units to generate the set-up for a particular problem. About this same time you become proficient in determining the number of significant figures you should report in your final answer. Refer to Chapter 2 for more information.

Atomic structure: Having a firm understanding of subatomic particles (protons, electrons, and neutrons), the nucleus, and the electron clouds is important when taking a chemistry course. Chapter 3 gives you an overview of these topics. You can also find information on electron configurations (the way to represent the various electrons in an atom), average atomic masses, and the mole concept. For an overview of these topics, see Chapters 3 and 4.

The Periodic Table and periodic properties: Chemistry I gave you the basics on electron configurations, ionization energies, sizes of atoms, and a host of other topics related to the periodic table. You definitely need this knowledge when studying Chem II. Chapter 3 gives you a brief overview.

Bonding: Chemical bonding, both ionic and covalent, form an important part of Chem I. Having a firm foundation on these topics is also important in Chem II. See Chapter 3 for a review.

Molecules, compounds, and chemical equations: Here is where chemical nomenclature was first introduced in your Chem I class. You may remember discussing chemical formulas, chemical names, and vice versa. Calculating molar masses and determining the empirical formula from percentage data is also important. You also figured out how to balance chemical equations. Chemical nomenclature is an absolute necessity of Chemistry II as well as the balancing of chemical equations and the determination of molar masses. For a review, refer to Chapter 4.

Reaction stoichiometry: You probably remember that this topic was a main crux of your Chem I course. You learned how to calculate how much — how much reactant, how much produce, how many moles, how many grams, and how many particles. Balanced chemical equations go hand in hand to allow you to do these calculations. You also focused on the basic reaction types and sometimes even a little solution stoichiometry. The reaction stoichiometry and the mole concept are of primary importance in Chem II. Flip to Chapter 4 to ensure you have a good understanding of these topics.

Solutions: More than likely you studied solution concentration units, especially molarity and molality, in your Chem I class. Solution concentrations are extremely important in Chem II. Refer to Chapter 5 for a review.

Gas properties: Many textbooks and Chem I instructors cover the properties of gases, including numerous gas laws and the kinetic molecular theory. Understanding the kinetic molecular theory also makes it easier to see how the various factors affect the kinetics of a reaction in Chem II. Check out Chapter 6 for more info.

Nuclear chemistry: Some instructors cover nuclear chemistry as part of the Chem I curriculum; some cover it in Chem II. Chapter 17 touches on what you need to know.

If you want more in-depth explanation of these topics, you can check out my book, Chemistry For Dummies, 2nd Edition (John Wiley & Sons, Inc.).

Looking to where you are now: General Chemistry II

In Chem II you can expect to encounter the following topics, but not necessarily in this exact order:

Chemical kinetics: A Chemistry II class usually covers this topic early after you finish reviewing the topics of Chem I. Kinetics is the study of the speed of reactions. Along with kinetics reaction mechanisms, the series of steps a reaction proceeds through in going from reactants to products is included. Chapter 7 covers kinetics.

Chemical equilibrium: This is the largest topic in most Chem II classes. An equilibrium is established when a chemical reaction goes from reactants to products and at the same time is also proceeding from products to reacts. These two reactions occur at the same reaction rate (speed). You can uncover all the different types of equilibriums: homogeneous, heterogeneous, acid-base, solubility, and complex-ion. You can also find out about ways to manipulate the equilibrium system so as to form as much product as possible. I discuss equilibrium in Chapters 8, 9, and 10.

Thermodynamics: Thermodynamics is another important topic of Chemistry II. Thermodynamics is basically the study of energy transfer. It builds on the thermochemistry concepts of Chem I, but it has the goal of being able to predict under what conditions a reaction is spontaneous. Chapter 11 covers thermodynamics.

Electrochemistry: The study of batteries and cells also appears in Chem II. You figure out how to balance redox reaction and then move on to electrochemical cells. You discover all about cells and batteries, including automobile batteries and flashlight cells. Chapter 12 explains electrochemistry in more depth.

Radioactivity: Chemistry II classes sometimes cover this topic. Sometimes Chemistry I classes cover it. Radioactivity essentially is the spontaneous decay of an unstable nucleus to a more stable one. This is the stuff of atomic bombs and nuclear power plants. Chapter 17 discusses radioactive decay, half-lives, fission, and fusion.

Other topics: Some instructors also cover organic chemistry and biochemistry. I cover these topics in Chapters 13 through 15.

Examining the Branches of Chemistry

As you go through your Chemisty II course, you may actually start to wonder what chemists do all day. Well, some make things (synthesis), others examine the properties of things (analysis), and others explain things (teach). But all chemists have a specialty area in which they have received more training. The following describes the general areas of chemistry.

Physical chemistry: This branch figures out how and why a chemical system behaves as it does. Physical chemists study the physical properties and behavior of matter and try to develop models and theories that describe this behavior. Especially keep this branch in mind when you’re studying thermodynamics in Chapter 11.

Analytical chemistry: This branch is highly involved in the determination of the properties of a substance (analysis). Chemists from this field of chemistry may be trying to find out what substances are in a mixture (qualitative analysis) or how much of a particular substance is present (quantitative analysis) in something. Analytical chemists typically work in industry in product development or quality control. If a chemical manufacturing process goes wrong and is costing that industry hundreds of thousands of dollars an hour, that quality control chemist is under a lot of pressure to fix it and fix it fast. A lot of instrumentation is used in analytical chemistry. Chapter 12, electrochemistry, is a typical topic studied by analytical chemists.

Inorganic chemistry: This branch is involved in the study of inorganic compounds such as salts. It includes the study of the structure and properties of these compounds. It also commonly involves the study of the individual elements of the compounds. Inorganic chemists probably say that this field is the study of everything except carbon, which they leave to the organic chemists. Inorganic chemists are interested in the descriptive chemistry of the elements.

Organic chemistry: This field is the study of carbon and its compounds. It’s probably the most organized of the areas of chemistry — with good reason. There are millions of organic compounds, with thousands more discovered or created each year. Industries such as the polymer industry, the petrochemical industry, and the pharmaceutical industry depend on organic chemists. Chapters 13 and 14 describe aspects of organic chemistry. Much more about organic chemistry can be found in Organic Chemistry II For Dummies (John Wiley & Sons, Inc.).

Biochemistry: This branch specializes in living organisms and systems. Biochemists study the chemical reactions that occur at the molecular level of an organism — the level where items are so small that people can’t directly see them. Biochemists study processes such as digestion, metabolism, reproduction, respiration, and so on. Sometimes, distinguishing between a biochemist and a molecular biologist is difficult because they both study living systems at a microscopic level. However, a biochemist really concentrates more on the reactions that are occurring. Check out Chapter 15 for a taste of biochemistry, but for a full meal see my book Biochemistry For Dummies (John Wiley & Sons, Inc.).

Biotechnology: This is a relatively new area of science that is commonly placed with chemistry. It’s the application of biochemistry and biology when creating or modifying genetic material or organisms for specific purposes. It’s used in such areas as cloning and the creation of disease-resistant crops, and it has the potential for eliminating genetic diseases in the future. I also suggest you check out my book Biochemistry For Dummies (John Wiley & Sons, Inc.) for more information.

Comparing Macroscopic versus Microscopic Viewpoints

As you go through your chemistry course, pay attention to the way your instructor shifts from talking about matter in terms of atoms and molecules and then shifts very naturally into the concrete world of grams and kilograms. These two viewpoints are called the microscopic viewpoint and the macroscopic viewpoint. Nearly all chemists, no matter what field they study, study the world around them in two ways:

Macroscopic view: This view is what you see, feel, and touch. This is the world of dirty lab coats — of mixing solutions and weighing out elements. This viewpoint is the world of experiments, or what some nonscientists call the real world.

Microscopic view: This view focuses on work with models and theories. Chemists may describe a chemical reaction, such as the Haber reaction to produce ammonia, in terms of individual atoms and molecules. This is the microscopic world.

Scientists are often so used to going back and forth between the two views that they don’t even realize that they’re doing so. An occurrence or observation in the macroscopic world generates an idea related to the microscopic world, and vice versa. You may find this flow of ideas disconcerting at first. You may have noticed this back and forth some in your Chemistry I studies; you’ll notice it more in your Chemistry II studies. You may need some adjusting to it before moving back and forth becomes second nature to you.