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@Fundamentals of environmental chemistry manahan

  1. 1. Manahan, Stanley E. "Frontmatter" Fundamentals of Environmental Chemistry Boca Raton: CRC Press LLC,2001
  2. 2. PREFACE TO THE SECOND EDITION ____________________________________________________ Fundamentals of Environmental Chemistry, 2nd edition, is written with two major objectives in mind. The first of these is to provide a reader having little or no background in chemistry with the fundamentals of chemistry needed for a trade, profession, or curriculum of study that requires a basic knowledge of these topics. The second objective of the book is to provide a basic coverage of modern environ- mental chemistry. This is done within a framework of industrial ecology and an emerging approach to chemistry that has come to be known as “green chemistry.” Virtually everyone needs some knowledge of chemistry. Unfortunately, this vital, interesting discipline “turns off” many of the very people who need a rudimentary knowledge of it. There are many reasons that this is so. For example, “chemophobia,” an unreasoned fear of insidious contamination of food, water, and air with chemicals at undetectable levels that may cause cancer and other maladies is widespread among the general population. The language of chemistry is often made too complex so that those who try to learn it retreat from concepts such as moles, orbitals, electronic configurations, chemical bonds, and molecular structure before coming to realize that these ideas are comprehensible and even interesting and useful. Fundamentals of Environmental Chemistry is designed to be simple and understandable, and it is the author’s hope that readers will find it interesting and applicable to their own lives. Without being overly simplistic or misleading, it seeks to present chemical principles in ways that even a reader with a minimal background in, or no particular aptitude for, science and mathematics can master the material in it and apply it to a trade, profession, or course of study. One of the ways in which Environmental Chemistry Fundamentals presents chemistry in a “reader-friendly” manner is through a somewhat unique organizational structure. In the first few pages of Chapter 1, the reader is presented with a “mini-course” in chemistry that consists of the most basic concepts and terms needed to really begin to understand chemistry. To study chemistry, it is necessary to know a few essential things—what an atom is, what is meant by elements, chemical formulas, chemical bonds, molecular mass. With these terms defined in very basic © 2001 CRC Press LLC
  3. 3. ways it is possible to go into more detail on chemical concepts without having to assume—as many introductory chemistry books do somewhat awkwardly—that the reader knows nothing of the meaning of these terms. Chapter 2 discusses matter largely on the basis of its physical nature and behavior, introducing physical and chemical properties, states of matter, the mole as a quantity of matter, and other ideas required to visualize chemical substances as physical entities. Chapters 3–5 cover the core of chemical knowledge constructed as a language in which elements and the atoms of which they are composed (Chapter 3) are presented as letters of an alphabet, the compounds made up of elements (Chapter 4) are analogous to words, the reactions by which compounds are synthesized and changed (Chapter 5) are like sentences in the chemical language, and the mathematical aspects hold it all together quantitatively. Chapters 6–8 constitute the remainder of material that is usually regarded as essential material in general chemistry. Chapter 9 presents a basic coverage of organic chemistry. Although this topic is often ignored at the beginning chemistry level, those who deal with the real world of environmental pollution, hazardous wastes, agricultural science, and other applied areas quickly realize that a rudimentary understanding of organic chemistry is essential. Chapter 10 covers biological chemistry, an area essential to understanding later material dealing with environmental and toxicological chemistry. Beyond Chapter 10, the book concentrates on environmental chemistry. Traditionally, discussion of environmental science has been devoted to the four traditional spheres—the hydrosphere, atmosphere, geosphere, and biosphere—that is, water, air, land, and life. It has usually been the case that, when mentioned at all in environmental science courses, human and industrial activities have been presented in terms of pollution and detrimental effects on the environment. Fundamentals of Environmental Chemistry goes beyond this narrow focus and addresses a fifth sphere of the environment, the anthrosphere, consisting of the things that humans make, use, and do. In taking this approach, it is recognized that humans have vast effects upon the environment and that they will use the other environmental spheres and the materials, energy, and life forms in them for perceived human needs. The challenge before humankind is to integrate the anthrosphere into the total environment and to direct human efforts toward the preservation and enhancement of the environment, rather than simply its exploita- tion. Environmental chemistry has a fundamental role in this endeavor, and this book is designed to assist the reader with the basic tools required to use environmental chemistry to enhance the environment upon which we all ultimately depend for our existence and well-being. Chapters 11–13 address the environmental chemistry of the hydrosphere. Chapter 11 discusses the fundamental properties of water, water supply and distri- bution, properties of bodies of water, and basic aquatic chemistry, including acid- base behavior, phase interactions, oxidation-reduction, chelation, and the important influences of bacteria, algae, and other life forms on aquatic chemistry. Chapter 12 deals specifically with water pollution and Chapter 13 with water treatment. Chapter 14 introduces the atmosphere and atmospheric chemistry, including the key concept of photochemistry. It discusses stratification of the atmosphere, Earth’s crucial energy balance between incoming solar energy and outgoing infrared energy, and weather and climate as they are driven by redistribution of energy and water in © 2001 CRC Press LLC
  4. 4. the atmosphere. Inorganic air pollutants, including nitrogen and sulfur oxides, carbon monoxide, and carbon dioxide (potentially a “pollutant” if excessive levels lead to detrimental greenhouse warming) are discussed in Chapter 14. Organic air pollutants and photochemical smog are the topics of Chapter 15. The geosphere is addressed in Chapters 17 and 18. Chapter 17 is a discussion of the composition and characteristics of the geosphere. Chapter 18 deals with soil and agriculture and addresses topics such as conservation tillage and the promise and potential pitfalls of genetically modified crops and food. Chapters 19–22 discuss anthrospheric aspects of environmental chemistry. Chapter 19 outlines industrial ecology as it relates to environmental chemistry. Chapter 20 covers the emerging area of “green chemistry,” defined as the sustainable exercise of chemical science and technology within the framework of good practice of industrial ecology so that the use and handling of hazardous substances are minimized and such substances are never released to the environment. Chapter 21 covers the nature, sources, and chemistry of hazardous substances. Chapter 22 addresses the reduction, treatment, and disposal of hazardous wastes within a framework of the practice of industrial ecology. Aspects of the biosphere are covered in several parts of the book. Chapter 10 provides a basic understanding of biochemistry as it relates to environmental chemistry. The influence of organisms on the hydrosphere is discussed in Chapters 11–13. Chapter 23 deals specifically with toxicological chemistry. Chapter 24 covers resources, both renewable and nonrenewable, as well as energy from fossil and renewable sources. The last two chapters outline analytical chemistry. Chapter 25 presents the major concepts and techniques of analytical chemistry. Chapter 26 discusses specific aspects of environmental chemical analysis, including water, air, and solid-waste analysis, as well as the analysis of xenobiotic species in biological systems. The author welcomes comments and questions from readers. He can be reached by e-mail at manahans@missouri.edu. © 2001 CRC Press LLC
  5. 5. Stanley E. Manahan is Professor of Chemistry at the University of Missouri- Columbia, where he has been on the faculty since 1965 and is President of ChemChar Research, Inc., a firm developing non-incinerative thermochemical waste treatment processes. He received his A.B. in chemistry from Emporia State University in 1960 and his Ph.D. in analytical chemistry from the University of Kansas in 1965. Since 1968 his primary research and professional activities have been in environmental chemistry, toxicological chemistry, and waste treatment. He teaches courses on environmental chemistry, hazardous wastes, toxicological chemistry, and analytical chemistry. He has lectured on these topics throughout the U.S. as an American Chemical Society Local Section tour speaker, in Puerto Rico, at Hokkaido University in Japan, and at the National Autonomous University in Mexico City. He was the recipient of the Year 2000 Award of the Environmental Chemistry Division of the Italian Chemical Society. Professor Manahan is the author or coauthor of approximately 100 journal articles in environmental chemistry and related areas. In addition to Fundamentals of Environmental Chemistry, 2nd ed., he is the author of Environmental Chemistry, 7th ed. (2000, Lewis Publishers), which has been published continuously in various editions since, 1972. Other books that he has written are Industrial Ecology: Environmental Chemistry and Hazardous Waste (Lewis Publishers, 1999), Environmental Science and Technology(Lewis Publishers, 1997), Toxicological Chemistry, 2nd ed. (Lewis Publishers, 1992), Hazardous Waste Chemistry, Toxicology and Treatment (Lewis Publishers, 1992), Quantitative Chemical Analysis, Brooks/Cole, 1986), and General Applied Chemistry, 2nd ed. (Willard Grant Press, 1982).
  6. 6. CONTENTS ____________________________________________________ CHAPTER 1 INTRODUCTION TO CHEMISTRY 1.1 Chemistry and Environmental Chemistry 1.2 A Mini-Course in Chemistry 1.3 The Building Blocks of Matter 1.4 Chemical Bonds and Compounds 1.5 Chemical Reactions and Equations 1.6 Numbers in Chemistry: Exponential notation 1.7 Significant Figures and Uncertainties in Numbers 1.8 Measurement and Systems of Measurement 1.9 Units of Mass 1.10 Units of Length 1.11 Units of Volume 1.12 Temperature, Heat, and Energy 1.13 Pressure 1.14 Units and Their Use in Calculations Chapter Summary CHAPTER 2 MATTER AND PROPERTIES OF MATTER 2.1 What is Matter? 2.2 Classification of Matter 2.3 Quantity of Matter: the Mole 2.4 Physical Properties of Matter 2.5 States of Matter 2.6 Gases 2.7 Liquids and Solutions 2.8 Solids 2.9 Thermal properties 2.10 Separation and Characterization of Matter Chapter Summary © 2001 CRC Press LLC
  7. 7. CHAPTER 3 ATOMS AND ELEMENTS 3.1 Atoms and Elements 3.2 The Atomic Theory 3.3 Subatomic Particles 3.4 The Basic Structure of the Atom 3.5 Development of the Periodic Table 3.6 Hydrogen, the Simplest Atom 3.7 Helium, the First Atom With a Filled Electron Shell 3.8 Lithium, the First Atom With BothInner and Outer Electrons 3.9 The Second Period, Elements 4–10 3.10 Elements 11–20, and Beyond 3.11 A More Detailed Look at Atomic Structure 3.12 Quantum and Wave Mechanical Models of Electrons in Atoms 3.13 Energy Levels of Atomic Orbitals 3.14 Shapes of Atomic Orbitals 3.15 Electron Configuration 3.16 Electrons in the First 20 Elements 3.17 Electron Configurations and the Periodic Table Chapter Summary Table of Elements CHAPTER 4 CHEMICAL BONDS, MOLECULES, AND COMPOUNDS 4.1 Chemical Bonds and Compound Formation 4.2 Chemical Bonding and the Octet Rule 4.3 Ionic Bonding 4.4 Fundamentals of Covalent Bonding 4.5 Covalent Bonds in Compounds 4.6 Some Other Aspects of Covalent Bonding 4.7 Chemical Formulas of Compounds 4.8 The Names of Chemical Compounds 4.9 Acids, Bases, and Salts Chapter Summary CHAPTER 5 CHEMICAL REACTIONS, EQUATIONS, AND STOICHIOMETRY 5.1 The Sentences of Chemistry 5.2 The Information in a Chemical Equation 5.3 Balancing Chemical Equations 5.4 Will a Reaction Occur? 5.5 How Fast Does a Reaction Go? 5.6 Classification of Chemical Reactions 5.7 Quantitative Information from Chemical Reactions 5.8 What is Stoichiometry and Why is it Important? Chapter Summary CHAPTER 6 ACIDS, BASES, AND SALTS 6.1 The Importance of Acids, Bases, and Salts 6.2 The Nature of Acids, Bases, and Salts 6.3 Conductance of Electricity by Acids, Bases, and Salts in Solution © 2001 CRC Press LLC
  8. 8. 6.4 Dissociation of Acids and Bases in Water 6.5 The Hydrogen Ion Concentration and Buffers 6.6 pH and the Relationship Between Hydrogen Ion and Hydroxide Ion Concentrations 6.7 Preparation of Acids 6.8 Preparation of Bases 6.9 Preparation of Salts 6.10 Acid Salts and Basic Salts 6.11 Names of Acids, Bases, and Salts Chapter Summary CHAPTER 7 SOLUTIONS 7.1 What are Solutions? Why are they Important? 7.2 Solvents 7.3 Water—A Unique Solvent 7.4 The Solution Process and Solubility 7.5 Solution Concentrations 7.6 Standard Solutions and Titrations 7.7 Physical Properties of Solutions 7.8 Solution Equilibria 7.9 Colloidal Suspensions Chapter Summary CHAPTER 8 CHEMISTRY AND ELECTRICITY 8.1 Chemistry and Electricity 8.2 Oxidation and Reduction 8.3 Oxidation-Reduction in Solution 8.4 The Dry Cell 8.5 Storage Batteries 8.6 Using Electricity to Make Chemical Reactions Occur 8.7 Electroplating 8.8 Fuel Cells 8.9 Solar Cells 8.10 Reaction Tendency 8.11 Effect of Concentration: Nernst Equation 8.12 Natural Water Purification Processes 8.13 Water Reuse and Recycling Chapter Summary CHAPTER 9 ORGANIC CHEMISTRY 9.1 Organic Chemistry 9.2 Hydrocarbons 9.3 Organic Functional Groups and Classes of Organic Compounds 9.4 Synthetic Polymers Chapter Summary CHAPTER 10 BIOLOGICAL CHEMISTRY 10.1 Biochemistry 10.2 Biochemistry and the Cell © 2001 CRC Press LLC
  9. 9. 10.3 Proteins 10.4 Carbohydrates 10.5 Lipids 10.6 Enzymes 10.7 Nucleic Acids 10.8 Recombinant DNA and Genetic Engineering 10.9 Metabolic Processes Chapter Summary CHAPTER 11 ENVIRONMENTAL CHEMISTRY OF WATER 11.1 Introduction 11.2 The Properties of Water, a Unique Substance 11.3 Sources and Uses of Water: the Hydrologic Cycle 11.4 The Characteristics of Bodies of Water 11.5 Aquatic Chemistry 11.6 Nitrogen Oxides in the Atmosphere 11.7 Metal Ions and Calcium in Water 11.8 Oxidation-Reduction 11.9 Complexation and Chelation 11.10 Water Interactions with Other Phases 11.11 Aquatic Life 11.12 Bacteria 11.13 Microbially Mediated Elemental Transistions and Cycles Chapter Summary CHAPTER 12 WATER POLLUTION 12.1 Nature and Types of Water Pollutants 12.2 Elemental Pollutants 12.3 Heavy Metal 12.4 Metalloid 12.5 Organically Bound Metals and Metalloids 12.6 Inorganic Species 12.7 Algal Nutrients and Eutrophications 12.8 Acidity, Alkalinity, and Salinity 12.9 Oxygen, Oxidants, and Reductants 12.10 Organic Pollutants 12.11 Pesticides in Water 12.12 Polychlorinated Biphenyls 12.13 Radionuclides in the Aquatic Environment Chapter Summary CHAPTER 13 WATER TREATMENT 13.1 Water Treatment and Water Use 13.2 Municipal Water Treatment 13.3 Treatment of Water For Industrial Use 13.4 Sewage Treatment 13.5 Industrial Wastewater Treatment 13.6 Removal of Solids 13.7 Removal of Calcium and Other Metals © 2001 CRC Press LLC
  10. 10. 13.8 Removal of Dissolved Organics 13.9 Removal of Dissolved Inorganics 13.10 Sludge 13.11 Water Disinfection 13.12 Natural Water Purification Processes 13.13 Water Reuse and Recycling Chapter Summary CHAPTER 14 THE ATMOSPHERE AND ATMOSPHERIC CHEMISTRY 14.1 The Atmosphere and Atmospheric Chemistry 14.2 Importance of the Atmosphere 14.3 Physical Characteristics of the Atmosphere 14.4 Energy Transfer in the Atmosphere 14.5 Atmospheric Mass Transfer, Meteorology, and Weather 14.6 Inversions and Air Pollution 14.7 Global Climate and Microclimate 14.8 Chemical and Photochemical Reactions in the Atmosphere 14.9 Acid–Base Reactions in the Atmosphere 14.10 Reactions of Atmospheric Oxygen 14.11 Reactions of Atmospheric Nitrogen 14.12 Atmospheric Water Chapter Summary CHAPTER 15 INORGANIC AIR POLLUTANTS 15.1 Introduction 15.2 Particles in the Atmosphere 15.3 The Composition of Inorganic Particles 15.4 Effects of Particles 15.5 Control of Particulate Emissions 15.6 Carbon Oxides 15.7 Sulfur Dioxide Sources and the Sulfur Cycle 15.8 Nitrogen Oxides in the Atmosphere 15.9 Acid Rain 15.10 Fluorine, Chlorine, and their Gaseous Compounds 15.11 Hydrogen Sulfide, Carbonyl Sulfide, and Carbon Disulfide Chapter Summary CHAPTER 16 ORGANIC AIR POLLUTANTS AND PHOTOCHEMICAL SMOG 16.1 Organic Compounds in the Atmosphere 16.2 Organic Compounds from Natural Sources 16.3 Pollutant Hydrocarbons 16.4 Nonhydrocarbon Organic Compounds in the Atmosphere 16.5 Photochemical Smog 16.6 Smog-Forming Automotive Emissions 16.7 Smog-Forming Reactions of Organic Compounds in the Atmosphere 16.8 Mechanisms of Smog Formation © 2001 CRC Press LLC
  11. 11. 16.9 Inorganic Products from Smog 16.10 Effects of Smog Chapter Summary CHAPTER 17 THE GEOSPHERE AND GEOCHEMISTRY 17.1 Introduction 17.2 The Nature of Solids in the Geosphere 17.3 Physical Form of the Geosphere 17.5 Clays 17.6 Geochemistry 17.7 Groundwater in the Geosphere 17.8 Environmental Aspects of the Geosphere 17.9 Earthquakes 17.10 Volcanoes 17.11 Surface Earth Movement 17.12 Stream and River Phenomena 17.13 Phenomena at the Land/Ocean Interface 17.14 Phenomena at the Land/Atmosphere Interface 17.15 Effects of Ice 17.16 Effects of Human Activities 17.17 Air Pollution and the Geosphere 17.18 Water Pollution and the Geosphere 17.19 Waste Disposal and the Geosphere Chapter Summary CHAPTER 18 SOIL ENVIRONMENTAL CHEMISTRY 18.1 Soil and Agriculture 18.2 Nature and Composition of Soil 18.3 Acid-Base and Ion Exchange Reactions in Soils 18.4 Macronutrients in Soil 18.5 Nitrogen, Phosphorus, and Potassium in Soil 18.6 Micronutrients in Soil 18.7 Fertilizers 18.8 Wastes and Pollutants in Soil 18.9 Soil Loss and Degradation 18.10 Genetic Engineering and Agriculture 18.11 Agriculture and Health Chapter Summary CHAPTER 19 INDUSTRIAL ECOLOGY AND ENVIRONMENTAL CHEMISTRY 19.1 Introduction and History 19.2 Industrial Ecosystems 19.3 The Five Major Components of an Industrial Ecosystem 19.4 Industrial Metabolism 19.5 Levels of Materials Utilization 19.6 Links to Other Environmental Spheres 19.7 Consideration of Environmental Impacts in Industrial Ecology 19.8 Three Key Attributes: Energy, Materials, Diversity © 2001 CRC Press LLC
  12. 12. 19.9 Life Cycles: Expanding and Closing the Materials Loop 19.10 Life-Cycle Assessment 19.11 Consumable, Recyclable, and Service (Durable) Products 19.12 Design for Environment 19.13 Overview of an Integrated Industrial Ecosystem 19.14 The Kalundborg Example 19.15 Societal Factors and the Environmental Ethic Chapter Summary CHAPTER 20 GREEN CHEMISTRY FOR A SUSTAINABLE FUTURE 20.1 Introduction 20.2 The Key Concept of Atom Economy 20.3 Hazard Reduction 20.4 Feedstocks 20.5 Reagents 20.6 Media 20.7 The Special Importance of Solvents 20.8 Synthetic and Processing Pathways 20.9 The Role of Catalysts 20.10 Biological Alternatives 20.11 Applications of Green Chemistry Chapter Summary CHAPTER 21 NATURE, SOURCES, AND ENVIRONMENTAL CHEMISTRY OF HAZARDOUS WASTES 21.1 Introduction 21.2 Classification of Hazardous Substances and Wastes 21.3 Sources of Wastes 21.4 Flammable and Combustible Substances 21.5 Reactive Substances 21.6 Corrosive Substances 21.7 Toxic Substances 21.8 Physical Forms and Segregation of Wastes 21.9 Environmental Chemistry of Hazardous Wastes 21.10 Physical and Chemical Properties of Hazardous Wastes 21.11 Transport, Effects, and Fates of Hazardous Wastes 21.12 Hazardous Wastes and the Anthrosphere 21.13 Hazardous Wastes in the Geosphere 21.14 Hazardous Wastes in the Hydrosphere 21.15 Hazardous Wastes in the Atmosphere 21.16 Hazardous Wastes in the Biosphere Chapter Summary CHAPTER 22 INDUSTRIAL ECOLOGY FOR WASTE MINIMIZATION, UTILIZATION, AND TREATMENT 22.1 Introduction 22.2 Waste Reduction and Minimization 22.3 Recycling © 2001 CRC Press LLC
  13. 13. 22.4 Physical Methods of Waste Treatment 22.5 Chemical Treatment: An Overview 22.6 Photolytic Reactions 22.7 Thermal Treatment Methods 22.8 Biodegradation of Wastes 22.9 Land Treatment and Composting 22.10 Preparation of Wastes for Disposal 22.11 Ultimate Disposal of Wastes 22.12 Leachate and Gas Emissions 22.13 In-Situ Treatment Chapter Summary CHAPTER 23 TOXICOLOGICAL CHEMISTRY 23.1 Introduction to Toxicology and Toxicological Chemistry 23.2 Dose-Response Relationships 23.3 Relative Toxicities 23.4 Reversibility and Sensitivity 23.5 Xenobiotic and Endogenous Substances 23.6 Toxicological Chemistry 23.7 Kinetic Phase and Dynamic Phase 23.8 Teratogenesis, Mutagenesis, Carcinogenesis, and Effects on the Immune and Reproductive Systems 23.9 ATSDR Toxicological Profiles 23.10 Toxic Elements and Elemental Forms 23.11 Toxic Inorganic Compounds 23.12 Toxic Organometallic Compounds 23.13 Toxicological Chemistry of Organic Compounds Chapter Summary CHAPTER 24 INDUSTRIAL ECOLOGY, RESOURCES, AND ENERGY 24.1 Introduction 24.2 Minerals in the Geosphere 24.3 Extraction and Mining 24.4 Metals 24.5 Metal Resources and Industrial Ecology 24.6 Nonmetal Mineral Resources 24.7 Phosphates 24.8 Sulfur 24.9 Wood—a Major Renewable Resource 24.10 The Energy Problem 24.11 World Energy Resources 24.12 Energy Conservation 24.13 Energy Conversion Processes 24.14 Petroleum and Natural Gas 24.15 Coal 24.16 Nuclear Fission Power 24.17 Nuclear Fusion Power 24.18 Geothermal Energy © 2001 CRC Press LLC
  14. 14. 24.19 The Sun: an Ideal Energy Source 24.20 Energy from Biomass 24.21 Future Energy Sources 24.22 Extending Resources through the Practice of Industrial Ecology Chapter Summary CHAPTER 25 FUNDAMENTALS OF ANALYTICAL CHEMISTRY 25.1 Nature and Importance of Chemical Analysis 25.2 The Chemical Analysis Process 25.3 Major Categories of Chemical Analysis 25.4 Error and Treatment of Data 25.5 Gravimetric Analysis 25.6 Volumetric Analysis: Titration 25.7 Spectrophotometric Methods 25.8 Electrochemical Methods of Analysis 25.9 Chromatography 25.10 Mass Spectrometry 25.11 Automated Analyses 25.12 Immunoassay Screening Chapter Summary CHAPTER 26 ENVIRONMENTAL AND XENOBIOTICS ANALYSIS 26.1 Introduction to Environmental Chemical Analysis 26.2 Analysis of Water Samples 26.3 Classical Methods of Water Analysis 26.4 Instrumental Methods of Water Analysis 26.5 Analysis of Wastes and Solids 26.6 Toxicity Characteristic Leaching Procedure 26.7 Atmospheric Monitoring 26.8 Analysis of Biological Materials and Xenobiotics Chapter Summary © 2001 CRC Press LLC
  15. 15. Manahan, Stanley E. "INTRODUCTION TO CHEMISTRY" Fundamentals of Environmental Chemistry Boca Raton: CRC Press LLC,2001
  16. 16. 1 INTRODUCTION TO CHEMISTRY ____________________________________________________ 1.1 CHEMISTRY AND ENVIRONMENTAL CHEMISTRY Chemistry is defined as the science of matter. Therefore, it deals with the air we breathe, the water we drink, the soil that grows our food, and vital life substances and processes. Our own bodies contain a vast variety of chemical substances and are tremendously sophisticated chemical factories that carry out an incredible number of complex chemical processes. There is a tremendous concern today about the uses—and particularly the mis- uses—of chemistry as it relates to the environment. Ongoing events serve as constant reminders of threats to the environment ranging from individual exposures to toxicants to phenomena on a global scale that may cause massive, perhaps cata- strophic, alterations in climate. These include, as examples, evidence of a perceptible warming of climate; record weather events—particularly floods—in the United States in the 1990s; and air quality in Mexico City so bad that it threatens human health. Furthermore, large numbers of employees must deal with hazardous substances and wastes in laboratories and the workplace. All such matters involve environmental chemistry for understanding of the problems and for arriving at solutions to them. Environmental chemistry is that branch of chemistry that deals with the origins, transport, reactions, effects, and fates of chemical species in the water, air, earth, and living environments and the influence of human activities thereon.1 A related discipline, toxicological chemistry, is the chemistry of toxic substances with empha- sis upon their interaction with biologic tissue and living systems.2 Besides its being an essential, vital discipline in its own right, environmental chemistry provides an excellent framework for the study of chemistry, dealing with “general chemistry,” organic chemistry, chemical analysis, physical chemistry, photochemistry, geo- chemistry, and biological chemistry. By necessity it breaks down the barriers that tend to compartmentalize chemistry as it is conventionally addressed. Therefore, this book is written with two major goals—to provide an overview of chemical science within an environmental chemistry framework and to provide the basics of environmental © 2001 CRC Press LLC
  17. 17. chemistry for those who need to know about this essential topic for their professions or for their overall education. 1.2 A MINI-COURSE IN CHEMISTRY It is much easier to learn chemistry if one already knows some chemistry! That is, in order to go into any detail on any chemical topic, it is extremely helpful to have some very rudimentary knowledge of chemistry as a whole. For example, a crucial part of chemistry is an understanding of the nature of chemical compounds, the chemical formulas used to describe them, and the chemical bonds that hold them together; these are topics addressed in Chapter 3 of this book. However, to understand these concepts, it is very helpful to know some things about the chemical reactions by which chemical compounds are formed, as addressed in Chapter 4. To work around this problem, Chapter 1 provides a highly condensed, simplified, but meaningful overview of chemistry to give the reader the essential concepts and terms required to understand more-advanced chemical material. 1.3 THE BUILDING BLOCKS OF MATTER All matter is composed of only about a hundred fundamental kinds of matter called elements. Each element is made up of very small entities called atoms; all atoms of the same element behave identically chemically. The study of chemistry, therefore, can logically begin with elements and the atoms of which they are composed. Subatomic Particles and Atoms Figure 1.1 represents an atom of deuterium, a form of the element hydrogen. It is seen that such an atom is made up of even smaller subatomic particles—positively charged protons, negatively charged electrons, and uncharged (neutral) neutrons. Protons and neutrons have relatively high masses compared with electrons and are contained in the positively charged nucleus of the atom. The nucleus has essentially all the mass, but occupies virtually none of the volume, of Electron “cloud” Nucleus n+ - Figure 1.1 Representation of a deuterium atom. The nucleus contains one proton (+) and one neutron (n). The electron (-) is in constant, rapid motion around the nucleus, forming a cloud of nega- tive electrical charge, the density of which drops off with increasing distance from the nucleus. © 2001 CRC Press LLC
  18. 18. the atom. An uncharged atom has the same number of electrons as protons. The electrons in an atom are contained in a cloud of negative charge around the nucleus that occupies most of the volume of the atom. Atoms and Elements All of the literally millions of different substances are composed of only around 100 elements. Each atom of a particular element is chemically identical to every other atom and contains the same number of protons in its nucleus. This number of protons in the nucleus of each atom of an element is the atomic number of the element. Atomic numbers are integers ranging from 1 to more than 100, each of which denotes a particular element. In addition to atomic numbers, each element has a name and a chemical symbol, such as carbon, C; potassium, K (for its Latin name kalium); or cadmium, Cd. In addition to atomic number, name, and chemical symbol, each element has an atomic mass (atomic weight). The atomic mass of each element is the average mass of all atoms of the element, including the various isotopes of which it consists. The atomic mass unit, u (also called the dalton), is used to express masses of individual atoms and molecules (aggregates of atoms). These terms are summarized in Figure 1.2. - An atom of carbon, symbol C. Each C atom has 6 protons (+) in its nucleus, so the atomic number of C is 6. The atomic mass of C is 12. An atom of nitrogen, symbol N. Each N atom has 7 protons (+) in its nucleus, so the atomic number of N is 7. The atomic mass of N is 14. 6+ 6n 7+ 7n- - - - - - - - - - - - Figure 1.2 Atoms of carbon and nitrogen Although atoms of the same element are chemically identical, atoms of most elements consist of two or more isotopes that have different numbers of neutrons in their nuclei. Some isotopes are radioactive isotopes or radionuclides, which have unstable nuclei that give off charged particles and gamma rays in the form of radioactivity. This process of radioactive decay changes atoms of a particular element to atoms of another element. © 2001 CRC Press LLC
  19. 19. Throughout this book reference is made to various elements. A list of the known elements is given on page 120 at the end of Chapter 3. Fortunately, most of the chemistry covered in this book requires familiarity with only about 25 or 30 elements. An abbreviated list of a few of the most important elements that the reader should learn at this point is given in Table 1.1. Table 1.1 List of Some of the More Important Common Elements Element Symbol Atomic Number Atomic Mass (relative to carbon-12) Argon Ar 18 39.948 Bromine Br 35 79.904 Calcium Ca 20 40.08 Carbon C 6 12.01115 Chlorine Cl 17 35.453 Copper Cu 29 63.546 Fluorine F 9 18.998403 Helium He 2 4.00260 Hydrogen H 1 1.0080 Iron Fe 26 55.847 Magnesium Mg 12 24.305 Mercury Hg 80 200.59 Neon Ne 10 20.179 Nitrogen N 7 14.0067 Oxygen O 8 15.9994 Potassium K 19 39.0983 Silicon Si 14 28.0855 Sodium Na 11 22.9898 Sulfur S 16 32.06 The Periodic Table When elements are considered in order of increasing atomic number, it is observed that their properties are repeated in a periodic manner. For example, elements with atomic numbers 2, 10, and 18 are gases that do not undergo chemical reactions and consist of individual molecules, whereas those with atomic numbers larger by one—3, 11, and 19—are unstable, highly reactive metals. An arrangement of the elements in a manner that reflects this recurring behavior is known as the periodic table (Figure 1.3). The periodic table is extremely useful in understanding chemistry and predicting chemical behavior. The entry for each element in the periodic table gives the element’s atomic number, name, symbol, and atomic mass. More-detailed versions of the table include other information as well. © 2001 CRC Press LLC
  20. 20. © 2001 CRC Press LLC
  21. 21. Features of the Periodic Table The periodic table gets its name from the fact that the properties of elements are repeated periodically in going from left to right across a horizontal row of elements. The table is arranged such that an element has properties similar to those of other elements above or below it in the table. Elements with similar chemical properties are called groups of elements and are contained in vertical columns in the periodic table. 1.4. CHEMICAL BONDS AND COMPOUNDS Only a few elements, particularly the noble gases, exist as individual atoms; most atoms are joined by chemical bonds to other atom