1 Chemistry Is a Molecular Science 1
Looking at the World of Atoms and Molecules 1
1.1 CHEMISTRY IS INTEGRAL TO OUR LIVES 2
1.2 SCIENCE IS A WAY OF UNDERSTANDING THE UNIVERSE 5
A Study of Sea Butterflies Illustrates the Process of Science 6
Reproducibility and an Attitude of Inquiry Are Essential Components of Science 8
A Theory Is a Single Idea That Has Great Explanatory Power 9
Science Has Limitations 9
Science Can Lead to Profound New Ideas 10
Science Helps Us Learn the Rules of Nature 11
1.3 SCIENTISTS MEASURE PHYSICAL QUANTITIES 12
CALCULATION CORNER UNIT CONVERSION 12
1.4 MASS IS HOW MUCH AND VOLUME IS HOW SPACIOUS 14
HANDS-ON CHEMISTRY PENNY FINGERS 15
HANDS-ON CHEMISTRY DECISIVE DIMENSIONS 16
1.5 ENERGY IS THE MOVER OF MATTER 18
1.6 TEMPERATURE IS A MEASURE OF HOW HOT—HEAT IT IS NOT 19
1.7 THE PHASE OF A MATERIAL DEPENDS ON THE MOTION OF ITS PARTICLES 22
Familiar Terms Are Used to Describe Changing Phases 23
HANDS-ON CHEMISTRY HOT-WATER BALLOON 24
1.8 DENSITY IS THE RATIO OF MASS TO VOLUME 25
CALCULATION CORNER MANIPULATING AN ALGEBRAIC EQUATION 27
IN PERSPECTIVE 27
A Word about Chapter Endmatter from the Author 28
IN THE SPOTLIGHT PSEUDOSCIENCE 36
2 Elements of Chemistry 39
Understanding Chemistry through Its Language 39
2.1 MATTER HAS PHYSICAL AND CHEMICAL PROPERTIES 40
HANDS-ON CHEMISTRY FIRE WATER 44
Determining Whether a Change Is Physical Or Chemical Can Be Difficult 45
2.2 ATOMS ARE THE FUNDAMENTAL COMPONENTS OF ELEMENTS 47
2.3 ELEMENTS CAN COMBINE TO FORM COMPOUNDS 49
Compounds Are Named According to the Elements They Contain 50
HANDS-ON CHEMISTRY OXYGEN BUBBLE BURSTS 51
2.4 MOST MATERIALS ARE MIXTURES 52
Mixtures Can Be Separated by Physical Means 53
HANDS-ON CHEMISTRY BOTTOMS UP AND BUBBLES OUT 55
2.5 CHEMISTS CLASSIFY MATTER AS PURE OR IMPURE 55
CALCULATION CORNER HOW PURE IS PURE? 57
2.6 ELEMENTS ARE ORGANIZED IN THE PERIODIC TABLE BY THEIR PROPERTIES 59
A Period Is a Horizontal Row,a Group a Vertical Column 61
IN PERSPECTIVE 64
IN THE SPOTLIGHT EXTENDING THE HUMAN LIFE SPAN 72
3 Discovering the Atom and Subatomic Particles 75
Where We've Been and What We Now Know 75
3.1 CHEMISTRY DEVELOPED OUT OF OUR INTEREST IN MATERIALS 76
3.2 LAVOISIER LAID THE FOUNDATION OF MODERN CHEMISTRY 77
Mass Is Conserved in a Chemical Reaction 77
HANDS-ON CHEMISTRY AIR OUT 79
Proust Proposed the Law of Definite Proportions 80
HANDS-ON CHEMISTRY COLLECTING BUBBLES 81
3.3 DALTON DEDUCED THAT MATTER IS MADE OF ATOMS 81
CALCULATION CORNER FINDING OUT HOW MUCH OF A CHEMICAL REACTS 82
Dalton Defended His Atomic Hypothesis Against Experimental Evidence 83
Mendeleev Used Known Relative Atomic Masses to Create the Periodic Table 85
3.4 THE ELECTRON WAS THE FIRST SUBATOMIC PARTICLE DISCOVERED 87
HANDS-ON CHEMISTRY BENDING ELECTRONS 90
3.5 THE MASS OF AN ATOM IS CONCENTRATED IN ITS NUCLEUS 90
3.6 THE ATOMIC NUCLEUS IS MADE OF PROTONS AND NEUTRONS 92
CALCULATION CORNER CALCULATING ATOMIC MASS 95
IN PERSPECTIVE 96
IN THE SPOTLIGHT NANOTECHNOLOGY 104
4 The Atomic Nucleus 107
Know Nukes4.1 THE CATHODE RAY LED TO THE DISCOVERY OF RADIOACTIVITY 108
The Three Major Products of Radioactivity Are Alpha,Beta,and Gamma Rays 110
4.2 RADIOACTIVITY IS A NATURAL PHENOMENON 112
Rems Are Units of Radiation 112
HANDS-ON CHEMISTRY PERSONAL RADIATION 114
4.3 RADIOACTIVE ISOTOPES ARE USEFUL AS TRACERS AND FOR MEDICAL IMAGING 115
4.4 RADIOACTIVITY RESULTS FROM AN IMBALANCE OF FORCES IN THE NUCLEUS 116
4.5 A RADIOACTIVE ELEMENT CAN TRANSMUTE TO A DIFFERENT ELEMENT 119
4.6 THE SHORTER THE HALF-LIFE,THE GREATER THE RADIOACTIVITY 120
HANDS-ON CHEMISTRY RADIOACTIVE PAPER CLIPS 122
4.7 ISOTOPIC DATING MEASURES THE AGE OF A MATERIAL 123
4.8 NUCLEAR FISSION IS THE SPLITTING OF THE ATOMIC NUCLEUS 125
Nuclear Fission Reactors Convert Nuclear Energy to Electrical Energy 128
The Breeder Reactor Breeds Its Own Fuel 129
4.9 NUCLEAR ENERGY COMES FROM NUCLEAR MASS AND VICE VERSA 130
4.10 NUCLEAR FUSION IS THE COMBINING OF ATOMIC NUCLEI 132
The Holy Grail of Nuclear Research Today Is Controlled Fusion 133
IN PERSPECTIVE 134
IN THE SPOTLIGHT MERCURY EMISSIONS 140
5 Atomic Models 143
Virtual Handles on the Very Real5.1 MODELS HELP US VISUALIZE THE INVISIBLE WORLD OF ATOMS 144
5.2 LIGHT IS A FORM OF ENERGY 147
5.3 ATOMS CAN BE IDENTIFIED BY THE LIGHT THEY EMIT 150
HANDS-ON CHEMISTRY SPECTRAL PATTERNS 151
5.4 NIELS BOHR USED THE QUANTUM HYPOTHESIS TO EXPLAIN ATOMIC SPECTRA 151
5.5 ELECTRONS EXHIBITWAVE PROPERTIES 155
HANDS-ON CHEMISTRY RUBBER WAVES 157
Probability Clouds and Atomic Orbitals Help Us Visualize Electron Waves 157
HANDS-ON CHEMISTRY QUANTIZED WHISTLE 160
5.6 ENERGY-LEVEL DIAGRAMS DESCRIBE HOW ORBITALS ARE OCCUPIED 161
5.7 ORBITALS OF SIMILAR ENERGIES CAN BE GROUPED INTO SHELLS 165
5.8 THE PERIODIC TABLE HELPS US PREDICT PROPERTIES OF ELEMENTS 168
The Smallest Atoms Are at the Upper Right of the Periodic Table 170
The Smallest Atoms Have the Most Strongly Held Electrons 172
IN PERSPECTIVE 174
IN THE SPOTLIGHT QUARKS AND LEPTONS 182
6 Chemical Bonding and Molecular Shapes 185
How Atoms Connect to One Another 185
6.1 AN ATOMIC MODEL IS NEEDED TO UNDERSTAND HOW ATOMS BOND 186
6.2 ATOMS CAN LOSE OR GAIN ELECTRONS TO BECOME IONS 187
Molecules Can Form Ions 190
6.3 IONIC BONDS RESULT FROM A TRANSFER OF ELECTRONS 191
HANDS-ON CHEMISTRY UP CLOSE WITH CRYSTALS 193
6.4 COVALENT BONDS RESULT FROM A SHARING OF ELECTRONS 194
6.5 VALENCE ELECTRONS DETERMINE MOLECULAR SHAPE 198
Molecular Shape Is Defined by Where the Substituent Atoms Are 201
HANDS-ON CHEMISTRY GUMDROP MOLECULES 203
6.6 POLAR COVALENT BONDS RESULT FROM AN UNEVEN SHARING OF ELECTRONS 203
6.7 MOLECULAR POLARITY RESULTS FROM AN UNEVEN DISTRIBUTION OF ELECTRONS 206
IN PERSPECTIVE 211
IN THE SPOTLIGHT WATER FLUORIDATION 218
7 Molecular Mixing 221
How Molecules Attract One Another 221
7.1 SUBMICROSCOPIC PARTICLES ELECTRICALLY ATTRACT ONE ANOTHER 222
Ions and Polar Molecules Attract One Another 222
Polar Molecules Attract Other Polar Molecules 223
Polar Molecules Can Induce Dipoles in Nonpolar Molecules 224
Atoms and Nonpolar Molecules Can Form Temporary Dipoles on Their Own 225
HANDS-ON CHEMISTRY CIRCULAR RAINBOWS 228
7.2 A SOLUTION IS A SINGLE-PHASE HOMOGENEOUS MIXTURE 228
CALCULATION CORNER CALCULATING FOR SOLUTIONS 232
HANDS-ON CHEMISTRY OVERFLOWING SWEETNESS 233
7.3 SOLUBILITY IS A MEASURE OF HOW WELL A SOLUTE DISSOLVES 233
Solubility Changes with Temperature 236
Gases Are More Soluble at Low Temperatures and High Pressures 236
HANDS-ON CHEMISTRY CRYSTAL CRAZY 238
Nonpolar Gases Readily Dissolve in Perfluorocarbons 239
7.4 SOAP WORKS BY BEING BOTH POLAR AND NONPOLAR 240
Detergents Are Synthetic Soaps 242
Hard Water Makes Soap Less Effective 242
IN PERSPECTIVE 244
IN THE SPOTLIGHT PARTIALLY HYDROGENATED FATS 252
8 Those Incredible Water Molecules 255
Macroscopic Consequences of Molecular Stickiness 255
8.1 WATER MOLECULES FORM AN OPEN CRYSTALLINE STRUCTURE IN ICE 256
HANDS-ON CHEMISTRY A SLICE OF ICE 258
8.2 FREEZING AND MELTING GO ON AT THE SAME TIME 259
Water Is Densest at 4℃ 261
8.3 THE BEHAVIOR OF LIQUID WATER IS THE RESULT OF THE STICKINESS OF WATER MOLECULES 263
The Surface of Liquid Water Behaves Like an Elastic Film 264
Capillary Action Results from the Interplay of Adhesive and Cohesive Forces 266
8.4 WATER MOLECULES MOVE FREELY BETWEEN THE LIQUID AND GASEOUS PHASES 267
Boiling is Evaporation Beneath a Liquid Surface 271
8.5 IT TAKES A LOT OF ENERGY TO CHANGE THE TEMPERATURE OF LIQUID WATER 274
CALCULATION CORNER HOW HEAT CHANGES TEMPERATURE 276
Global Climates Are Influenced by Water's High Specific Heat 276
HANDS-ON CHEMISTRY RACING TEMPERATURES 278
8.6 A PHASE CHANGE REQUIRES THE INPUT OR OUTPUT OF ENERGY 278
IN PERSPECTIVE 281
IN THE SPOTLIGHT GLOBAL WARMING AND THE KYOTO PROTOCOL 288
9 An Overview of Chemical Reactions 291
How Reactants React to Form Products 291
9.1 CHEMICAL REACTIONS ARE REPRESENTED BY CHEMICAL EQUATIONS 292
9.2 CHEMISTS USE RELATIVE MASSES TO COUNT ATOMS AND MOLECULES 294
The Periodic Table Helps Us Convert Between Grams and Moles 297
CALCULATION CORNER FIGURING MASSES OF REACTANTS AND PRODUCTS 299
9.3 REACTION RATE IS INFLUENCED BY CONCENTRATION AND TEMPERATURE 299
9.4 CATALYSTS INCREASE THE RATE OF CHEMICAL REACTIONS 305
9.5 CHEMICAL REACTIONS CAN BE EITHER EXOTHERMIC OR ENDOTHERMIC 307
An Exothermic Reaction Involves a Net Release of Energy 309
An Endothermic Reaction Involves a Net Absorption of Energy 310
HANDS-ON CHEMISTRY WARMING AND COOLING WATER MIXTURES 312
9.6 ENTROPY IS A MEASURE OF DISPERSED ENERGY 312
Substances Contain Dispersed Energy 313
Heats of Reaction Affect Entropy 315
The Laws of Thermodynamics 317
IN PERSPECTIVE 318
IN THE SPOTLIGHT DOUBLING TIME 326
10 Acids and Bases 329
Transferring Protons 329
10.1 ACIDS DONATE AND BASES ACCEPT POSITIVE CHARGE 330
The Br？nsted-Lowry Definition Focuses on Protons 331
The Lewis Definition Focuses on Lone Pairs 334
A Salt Is the Ionic Product of an Acid-Base Reaction 335
10.2 SOME ACIDS AND BASES ARE STRONGER THAN OTHERS 337
10.3 SOLUTIONS CAN BE ACIDIC,BASIC,OR NEUTRAL 340
The pH Scale Is Used to Describe Acidity 343
CALCULATION CORNER LOGARITHMS AND pH 344
HANDS-ON CHEMISTRY RAINBOW CABBAGE 345
10.4 RAINWATER IS ACIDIC AND OCEAN WATER IS BASIC 345
10.5 BUFFER SOLUTIONS RESIST CHANGES IN pH 350
IN PERSPECTIVE 353
IN THE SPOTLIGHT HAIR AND SKIN CARE 360
11 Oxidation and Reduction 363
Transferring Electrons 363
11.1 OXIDATION IS THE LOSS OF ELECTRONS AND REDUCTION IS THE GAIN OF ELECTRONS 364
11.2 PHOTOGRAPHY WORKS BY SELECTIVE OXIDATION AND REDUCTION 366
HANDS-ON CHEMISTRY SILVER LINING 368
11.3 THE ENERGY OF FLOWING ELECTRONS CAN BE HARNESSED 368
The Electricity of a Battery Comes from Oxidation-Reduction Reactions 370
Fuel Cells Are Highly Efficient Sources of Electrical Energy 374
Electrical Energy Can Produce Chemical Change 377
11.4 OXYGEN IS RESPONSIBLE FOR CORROSION AND COMBUSTION 378
HANDS-ON CHEMISTRY SPLITTING WATER 378
IN PERSPECTIVE 382
IN THE SPOTLIGHT THE WONDER CHEMICAL,BUT... 388
12 Organic Compounds 391
A Survey of Carbon-Based Molecules 391
12.1 HYDROCARBONS CONTAIN ONLY CARBON AND HYDROGEN 392
12.2 UNSATURATED HYDROCARBoNS CONTAIN MULTIPLE BONDS 396
HANDS-ON CHEMISTRY TWISTING JELLY BEANS 398
12.3 ORGANIC MOLECULES ARE CLASSIFIED BY FUNCTIONAL GROUP 400
Alcohols Contain the Hydroxyl Group 401
Phenols Contain an Acidic Hydroxyl Group 402
The Oxygen of an Ether Group Is Bonded to Two Carbon Atoms 404
Amines Form Alkaline Solutions 405
Ketones,Aldehydes,Amides,Carboxylic Acids,and Esters All Contain a Carbonyl Group 407
12.4 ORGANIC MOLECULES CAN LINK TO FORM POLYMERS 411
Addition Polymers Result from the Joining Together of Monomers 413
Condensation Polymers Form with the Loss of Small Molecules 416
HANDS-ON CHEMISTRY RACING WATER DROPS 418
IN PERSPECTIVE 419
IN THE SPOTLIGHT THE GENETICS OF MUSCLE FITNESS 428
13 Chemicals of Life 431
The Nutrients That Make Up Our Bodies 431
13.1 BIOMOLECULES ARE PRODUCED AND UTILIZED IN CELLS 432
13.2 CARBOHYDRATES GIVE STRUCTURE AND ENERGY 433
Polysaccharides Are Complex Carbohydrates 434
HANDS-ON CHEMISTRY SPIT IN BLUE 437
13.3 LIPIDS ARE INSOLUBLE IN WATER 440
Fats Are Used for Energy and Insulation 440
Steroids Contain Four Carbon Rings 441
13.4 PROTEINS ARE POLYMERS OF AMINO ACIDS 444
Protein Structure Is Determined by Attractions Between Neighboring Amino Acids 444
Enzymes Are Biological Catalysts 451
13.5 NUCLEIC ACIDS CODE FOR PROTEINS 451
DNA Is the Template of Life 452
One Gene Codes for One Polypeptide 455
RNA Is Largely Responsible for Protein Synthesis 455
Genetic Engineering 458
13.6 VITAMINS ARE ORGANIC,MINERALS ARE INORGANIC 462
13.7 METABOLISM IS THE CYCLING OF BIOMOLECULES THROUGH THE BODY 465
13.8 THE FOOD PYRAMID SUMMARIZES A HEALTHFUL DIET 466
Carbohydrates Predominate in Most Foods 467
Unsaturated Fats Are Generally More Healthful Than Saturated Fats 470
Our Intake of Essential Amino Acids Should Be Carefully Monitored 471
HANDS-ON CHEMISTRY SIZZLE SOURCES 471
IN PERSPECTIVE 473
14 The Chemistry of Drugs 479
Understanding Drug Action 479
14.1 DRUGS ARE CLASSIFIED BY SAFETY,SOCIAL ACCEPTABI LITY,ORIGIN,AND BIOLOGICAL ACTIVITY 480
14.2 THE LOCK-AND-KEY MODEL GUIDES CHEMISTS IN SYNTHESIZING NEW DRUGS 482
14.3 CHEMOTHERAPY CURES THE HOST BY KILLING THE DISEASE 485
Sulfa Drugs and Antibiotics Treat Bacterial Infections 485
Chemotherapy Can Inhibit the Ability of Viruses to Replicate 487
Cancer Chemotherapy Attacks Rapidly Growing Cells 489
14.4 SOME DRUGS EITHER BLOCK OR MIMIC PREGNANCY 492
14.5 THE NERVOUS SYSTEM IS A NETWORK OF NEURONS 493
HANDS-ON CHEMISTRY DIFFUSING NEURONS 495
Neurotransmitters Include Norepinephrine,Acetylcholine,Dopamine,Serotonin,and GABA 495
14.6 PSYCHOACTIVE DRUGS ALTER THE MIND OR BEHAVIOR 497
Stimulants Activate the Stress Neurons 497
Hallucinogens and Cannabinoids Alter Perceptions 501
Depressants Inhibit the Ability of Neurons to Conduct Impulses 504
14.7 PAIN RELIEVERS INHIBIT THE TRANSMISSION OR PERCEPTION OF PAIN 507
14.8 DRUGS FOR THE HEART OPEN BLOOD VESSELS OR ALTER HEART RATE 511
IN PERSPECTIVE 513
15 Optimizing Food Production 519
From the Good Earth 519
15.1 HUMANS EAT AT ALL TROPHIC LEVELS 520
15.2 PLANTS REQUIRE NUTRIENTS 522
Plants Utilize Nitrogen,Phosphorus,and Potassium 522
Plants Also Utilize Calcium,Magnesium,and Sulfur 525
15.3 SOIL FERTILITY IS DETERMINED BY SOIL STRUCTURE AND NUTRIENT RETENTION 526
Soil Readily Retains Positively Charged Ions 527
HANDS-ON CHEMISTRY YOUR SOIL'S pH—A QUALITATIVE MEASURE 530
15.4 NATURAL AND SYNTHETIC FERTILIZERS HELP RESTORE SOIL FERTILITY 530
15.5 PESTICIDES KILL INSECTS,WEEDS,AND FUNGI 532
Insecticides Kill Insects 533
HANDS-ON CHEMISTRY CLEANING YOUR INSECTS 536
Herbicides Kill Weeds 536
Fungicides Kill Fungi 538
15.6 THERE IS MUCH TO LEARN FROM PAST AGRICULTURAL PRACTICES 538
15.7 HIGH AGRICULTURAL YIELDS CAN BE SUSTAINED WITH PROPER PRACTICES 541
Organic Farming Is Environmentally Friendly 542
Integrated Crop Management Is a Strategy for Sustainable Agriculture 542
15.8 A CROP CAN BE IMPROVED BY INSERTING A GENE FROM ANOTHER SPECIES 544
IN PERSPECTIVE 546
16 Fresh Water Resources 553
Our Roles and Responsibilities 553
16.1 WATER CIRCULATES THROUGH THE HYDROLOGIC CYCLE 554
16.2 COLLECTIVELY,WE CONSUME HUGE AMOUNTS OF WATER 556
HANDS-ON CHEMISTRY WATER WISER 558
16.3 WATER TREATMENT FACILITIES MAKE WATER SAFE FOR DRINKING 559
16.4 FRESH WATER CAN BE MADE FROM SALT WATER 561
HANDS-ON CHEMISTRY MICRO WATER PURIFIER 565
16.5 HUMAN ACTIVITIES CAN POLLUTE WATER 565
16.6 MICROORGANISMS IN WATER ALTER LEVELS OF DISSOLVED OXYGEN 568
16.7 WASTEWATER IS PROCESSED BY TREATMENT FACILITIES 569
Advanced Integrated Pond Systems Treat Wastewater 571
IN PERSPECTIVE 572
17 Air Resources 579
One Planet,One Atmosphere 579
17.1 EARTH'S ATMOSPHERE IS A MIXTURE OF GASES 580
CALCULATION CORNER DENSE AS AIR 582
HANDS-ON CHEMISTRY ATMOSPHERIC CAN-CRUSHER 583
17.2 GAS LAWS DESCRIBE THE BEHAVIOR OF GASES 583
Boyle's Law:Pressure and Volume 583
Charles's Law:Volume and Temperature 584
Avogadro's Law:Volume and Number of Particles 585
The Ideal Gas Law 586
CALCULATION CORNER HOT AIR BALLOONS 588
17.3 HUMAN ACTIVITIES HAVE INCREASED AIR POLLUTION 588
Aerosols and Particulates Facilitate Chemical Reactions Involving Pollutants 589
There Are Two Kinds of Smog 590
Catalytic Converters Reduce Automobile Emissions 593
17.4 STRATOSPHERIC OZONE PROTECTS EARTH FROM ULTRAVIOLET RADIATION 594
17.5 AIR POLLUTION MAY RESULT IN GLOBAL WARMING 597
Atmospheric Carbon Dioxide Is a Greenhouse Gas 598
The Potential Effects of Global Warming Are Uncertain 600
IN PERSPECTIVE 602
18 Material Resources 609
A Look at the Materials of Our Society 609
18.1 PAPER IS MADE OF CELLULOSE FIBERS 610
HANDS-ON CHEMISTRY PAPERMAKING 611
18.2 THE DEVELOPMENT OF PLASTICS INVOLVED EXPERIMENTATION AND DISCOVERY 612
Collodion and Celluloid Begin with Nitrocellulose 614
Bakelite Was the First Widely Used Plastic 614
The First Plastic Wrap Was Cellophane 615
Polymers Win in World War Ⅱ 616
Attitudes about Plastics Have Changed 618
18.3 METALS COME FROM THE EARTH'S LIMITED SUPPLY OF ORES 619
We Should Conserve and Recycle Metals 621
18.4 METAL-CONTAINING COMPOUNDS CAN BE CONVERTED TO METALS 622
Some Metals Are Most Commonly Obtained from Metal Oxides 623
Other Metals Are Most Commonly Obtained from Metal Sulfides 626
18.5 GLASS IS MADE PRIMARILY OF SILICATES 626
18.6 CERAMICS ARE HARDENED WITH HEAT 628
Ceramic Superconductors Have No Electrical Resistance 629
18.7 COMPOSITES COMBINE FIBERS AND A THERMOSET MEDIUM 630
HANDS-ON CHEMISTRY A COMPOSITE OF WHITE GLUE AND THREAD 631
IN PERSPECTIVE 632
19 Energy Resources 637
Managing for the Present and the Future 637
19.1 ELECTRICITY IS A CONVENIENT FORM OF ENERGY 638
What's a Watt? 639
CALCULATION CORNER KILOWATT-HOURS 639
19.2 FOSSIL FUELS ARE A WIDELY USED BUT LIMITED ENERGY SOURCE 640
Coal Is the Filthiest Fossil Fuel 643
Petroleum Is the King of Fossil Fuels 644
Natural Gas Is the Purest Fossil Fuel 645
19.3 THERE ARE TWO FORMS OF NUCLEAR ENERGY 646
Nuclear Fission Generates Some of Our Electricity 647
Nuclear Fusion Is a Potential Source of Clean Energy 650
19.4 WHAT ARE SUSTAINABLE ENERGY SOURCES? 651
19.5 WATER CAN BE USED TO GENERATE ELECTRICITY 652
Hydroelectric Power Comes from the Kinetic Energy of Flowing Water 652
Temperature Differences in the Ocean Can Generate Electricity 653
Geothermal Energy Comes from Earth's Interior 654
The Energy of Ocean Tides Can Be Harnessed 656
19.6 BIOMASS IS CHEMICAL ENERGY 656
Fuels Can Be Obtained from Biomass 657
Biomass Can Be Burned to Generate Electricity 658
19.7 ENERGY CAN BE HARNESSED FROM SUNLIGHT 658
Solar Heat Is Easily Collected 658
Solar Thermal Electric Generation Produces Electricity 659
HANDS-ON CHEMISTRY SOLAR POOL COVER 660
Wind Power Is Cheap and Widely Available 660
Photovoltaics Convert Sunlight Directly to Electricity 662
19.8 OUR FUTURE ECONOMY MAY BE BASED ON HYDROGEN 665
Fuel Cells Produce Electricity from Fuel 666
Photovoltaic Cells Can Be Used to Produce Hydrogen from Water 666
But Hydrogen May Not Be the Ultimate Solution 667
IN PERSPECTIVE 667