Chemistry 5th Edition

Book Preface

Today, as always, the science of chemistry, together with the other sciences that depend on it, stands at the forefront of discovery. Developing “greener” energy sources to power society and using our newfound knowledge of the
human genome to cure disease are but two of the areas that will occupy researchers in the chemical, biological, and engineering sciences for much of the 21st century. Addressing these and countless other challenges and opportunities depends on an understanding of the concepts you will learn in this course.
The impact of chemistry on your personal, everyday life is mind-boggling. Consider what the beginning of a typical day might look like from a chemical point of view. Molecules align in the liquid crystal display of your clock and electrons flow to create a noise. A cascade of neuronal activators arouses your brain, and you throw off a thermal insulator of manufactured polymer and jump in the shower to emulsify fatty substances on your skin and hair with purified water and formulated detergents. Then, you adorn yourself in an array of processed chemicals— pleasant-smelling pigmented materials suspended in cosmetic gels, dyed polymeric fibers, synthetic footwear, and metal-alloyed jewelry. Breakfast is a bowl of nutrient-enriched, spoilage-retarded cereal and milk, a piece of fertilizer-grown, pesticide-treated fruit, and a cup of a hot aqueous solution of stimulating alkaloid. After abrading your teeth with artificially flavored, dental-hardening agents in a colloidal dispersion, you’re ready to leave, so you grab your laptop (an electronic device containing ultrathin, microetched semiconductor layers powered by a series of voltaic cells), collect some books (processed cellulose and plastic, electronically printed with light- and oxygen-resistant inks), hop in your hydrocarbon-fueled, metal-vinyl-ceramic vehicle, electrically ignite a synchro-nized series of controlled gaseous explosions, and you’re off to class!
The influence of chemistry extends to the natural environment as well. The air, water, and land and the organisms that thrive there form a remarkably complex system of chemical interactions. While modern chemical products have enhanced the quality of our lives, their manufacture and use also pose increasing dangers, such as toxic wastes, acid rain, global warming, and ozone depletion. If our careless disregard of chemical principles has led to some of these problems, our careful adherence to the same principles is helping to solve them.
Perhaps the significance of chemistry is most profound when you contemplate the chemical nature of biology. Molecular events taking place within you right now allow your eyes to scan this page and your brain cells to translate fluxes of electric charge into thoughts. The most vital biological questions—How did life arise and evolve? How does an organism reproduce, grow, and age? What is the essence of health and disease?—ultimately have chemical answers.
This course comes with a bonus—the development of two mental skills you can apply to many fields. The first, common to all science courses, is the ability to solve problems systematically. The second is specific to chemistry, for as you comprehend its ideas, your mind’s eye will learn to see a hidden level of the universe, one filled with incredibly minute particles moving at fantastic speeds, colliding billions of times a second, and interacting in ways that determine how all the matter inside and outside of you behaves. This first chapter holds the keys to help you enter this new world.
IN THIS CHAPTER . . . We begin with fundamental definitions and concepts of matter and energy and their changes. Then, a brief discussion of chemistry’s historical origins leads to an overview of how scientists build models to study nature. We consider chemical problem solving, including unit conversion, modern systems of measurement—focusing on mass, length, volume, density, and temperature— and the manipulation of numbers in calculations. A final essay examines how modern chemists work with other scientists for society’s benefit.