A Problem-Solving Approach to Aquatic Chemistry James N. Jensen University at Buffalo John Wiley & Sons, Inc.
Table of Contents Partfc I^damental^^ 1_ Chapter 1: Getting Started with the Fundamental Concepts 3 1.1 Introduction 3 1.2 Why Calculate Chemical Species Concentrations? 3 1.3 Master Variables: The Importance of ph and pe 7 1.4 Properties of Water 8 1.5 Part I Road Map 9 1.6 Summary 10 1.7 Part I Case Study: Can Methylmercury Be Formed in Water? 10 Summary of Key Ideas 12 Chapter 2: Concentration Units 13 2.1 Introduction 13 2.2 Units Analysis 13 2.3 Molar Concentration Units 14 2.4 Mass Concentration Units 18 2.5 Dimensionless Concentration Units 21 2.6 Equivalents 22 2.7 Review of Units Interconversion 23 2.8 Common Concentration Units in the Gas Phase 23 2.9 Common Concentration Units in the Solid Phase 25 2.10 Activity 25 2.11 Summary 27 2.12 Part I Case Study: Can Methylmercury Be Formed in Water? 27 Summary of Key Ideas 28 Historical Note: Amadeo Avogadro and Avogadro's Number 29 Problems 30 Chapter 3: Thermodynamic Basis of Equilibrium 33 3.1 Introduction 33 3.2 Thermodynamic Properties 34 3.3 Why Do We Need Thermodynamics to Calculate Species Concentrations? 37 3.4 Thermodynamic Laws 41 3.5 Gibbs Free Energy 44 3.6 Properties of Thermodynamic Functions 46 3.7 Changes in Thermodynamic Properties During Chemical Reactions 49 3.8 Relating Gibbs Free Energy to Species Concentrations 54 3.9 Chemical Equilibrium and the Equilibrium Constant 59 3.10 Summary 60 3.11 Part I Case Study: Can Methylmercury Be Formed in Water? 61 Summary of Key Ideas 62 Historical Note: Josiah Willard Gibbs 63 Problems 63 vm
IX Chapter 4: Manipulating Equilibria 67 4.1 Introduction 67 4.2 Chemical and Mathematical Forms of Equilibrium 68 4.3 Units of Equilibrium Constants 70 4.4 Reversing Equilibria 72 4.5 Effects of Stoichiometry 73 4.6 Adding Equilibria 75 4.7 Creating Equilibria 76 4.8 Summary 82 4.9 Part I Case Study: Can Methylmercury Be Formed in Water? 82 Summary of Key Ideas 83 Historical Note: Henri-Louis Le Chatelier and Le Chatelier's Principle 84 Problems 85 ;Part II: Solution of Chemical Equilibrium Problems 87 Chapter 5: Getting Started with the Solution of Chemical Equilibrium Problems 89 5.1 Introduction 89 5.2 A Framework for Solving Equilibrium Problems 89 5.3 Introduction to Defining the Chemical System 91 5.4 Introduction to Enumerating Chemical Species 92 5.5 Introduction to Defining the Constraints on Species Concentrations 92 5.6 Road Map to Part II 94 5.7 Summary 95 5.8 Part II Case Study: Have You Had Your Zinc Today? 95 Summary of Key Ideas 96 Chapter 6: Setting Up Chemical Equilibrium Problems 97 6.1 Introduction 97 6.2 Defining the Chemical System 97 6.3 Enumerating Chemical Species 98 6.4 Defining Constraints on Species Concentrations 104 6.5 Review of Procedures for Setting Up Equilibrium Systems 111 6.6 Concise Mathematical Form for Equilibrium Systems: An Advanced Topic 112 6.7 Summary 113 6.8 Part II Case Study: Have You Had Your Zinc Today? 113 Summary of Key Ideas 117 Problems 117 Chapter 7: Algebraic Solution Techniques 121 7.1 Introduction 121 7.2 Background on Algebraic Solutions 121 7.3 Method of Substitution 123 7.4 Method of Approximation 126 7.5 Summary 133 7.6 Part II Case Study: Have You Had Your Zinc Today? 134 Summary of Key Ideas 137 Problems 138 x
Chapter 8: Graphical Solution Techniques 141 8.1 Introduction 141 8.2 Introduction to Log Concentration and pc-ph Diagrams 142 8.3 Using pc-ph Diagrams with More Complex Systems 148 8.4 Special Shortcuts for Monoprotic Acids 153 8.5 When Graphical Methods Fail: The Proton Condition 158 8.6 Conclusions 164 8.7 Part II Case Study: Have You Had Your Zinc Today? 165 Summary of Key Ideas 166 Problems 168 Chapter 9: Computer Solution Techniques 171 9.1 Introduction 171 9.2 Chapter Problem 171 9.3 Spreadsheet Solutions 172 9.4 Equilibrium Calculation Software 175 9.5 Nanoql 177 9.6 The Tableau Method and Other Equilibrium Calculation Programs 179 9.7 Summary 188 9.8 Part II Case Study: Have You Had Your Zinc Today? 189 Summary of Key Ideas 189 Problems 190 Part III: Acid-Base Equilibria in Homogenous Aqueous Systems 191 Chapter 10: Getting Started with Acid-Base Equilibria in Homogenous Aqueous Systems 193 10.1 Introduction 193 10.2 Homogeneous Systems 193 10.3 Types of Reactions in Homogeneous Systems 195 10.4 The Wonderful World of Acids and Bases 196 10.5 Part III Road Map 199 10.6 Summary 200 10.7 Part III Case Study: Acid Rain 200 : Summary of Key Ideas 201 Chapter 11: Acids and Bases 203 11.1 Introduction 203 11.2 Definitions of Acids and Bases 203 11.3 Acid and Base Strength 207 11.4 Polyprotic Acids 212 11.5 Distribution Functions (Alpha Values) 220 11.6 Summary 222 11.7 Part III Case Study: Acid Rain 222 Summary of Key Ideas 224 Problems 225 '
XI Chapter 12: Titrations 229 12.1 Introduction 229 12.2 Principles of-acid-base Titrations 231 12.3 Equivalence Points 234 12.4 Titration of Diprotic Acids 244 12.5 Buffers 247 12.6 Interpretation of Titration Curves with Complex Mixtures 256 12.7 Summary 259 12.8 Part III Case Study: Acid Rain 260 Summary of Key Ideas 262 Problems 264 Chapter 13: Alkalinity and Acidity 267 13.1 Introduction 267 13.2 Alkalinity and the Acid Neutralizing Capacity 267 13.3 Alkalinity and the Charge Balance 271 13.4 Characteristics of Alkalinity and Acidity 273 13.5 Using the Definitions of Alkalinity to Solve Problems 283 13.6 Effects of Other Weak Acids and Bases on Alkalinity 288 13.7 Summary 289 13.8 Part III Case Study: Acid Rain 290 Summary of Key Ideas 291 Problems 292 Part IV: Other Equilibria in Homogenous Aqueous Systems 295 Chapter 14: Getting Started with Other Equilibria in Homogenous Aqueous Systems 197 14.1 Introduction 297 14.2 Electron-sharing Reactions 297 14.3 Electron Transfer 300 14.4 Part IV Road Map 301 14.5 Summary 302 14.6 Part IV Case Study: Which Form of Copper Plating Should You Use? 302 Summary of Key Ideas 303 Chapter 15: Complexation 305 15.1 Introduction 305 15.2 Metals 305 15.3 Ligands 308 15.4 Equilibrium Calculations with Complexes 313 15.5 Systems with Several Metals and Ligands 321 15.6 Applications of Complexation Chemistry 329 15.7 Summary 330 15.8 Part IV Case Study: Which Form of Copper Plating Should You Use? 330 Summary of Key Ideas 333 Problems 334
xu Chapter 16: Oxidation and Reduction 337 16.1 Introduction 337 16.2 A Few Definitions 337 16.3 Balancing Redox Reactions 339 16.4 Which Redox Reactions Occur? 346 16.5 Redox Thermodynamics and Oxidant and Reductant Strength 347 16.6 Algebraic Equilibrium Calculations in Systems Undergoing Electron Transfer 353 16.7 Graphical Representations of Systems Undergoing Electron Transfer 358 16.8 Applying Redox Equilibrium Calculations to the Real World 372 16.9 Summary 374 16.10 Part IV Case Study: Which Form of Copper Plating Should You Use? 375 Summary of Key Ideas 377 Historical Note: Walther Hermann Nernst 378 Problems 379 Part V: Heterogeneous Systemsj 383_ Chapter 17: Getting Started with Heterogenous Systems 385 17.1 Introduction 385 17.2 Equilibrium Exchange Between Gas and Aqueous Phases 385 17.3 Equilibrium Exchange Between Solid and Aqueous Phases 387 17.4 Part V Road Map 388 17.5 Summary 388 17.6 Part V Case Study: The Killer Lakes 389 Summary of Key Ideas 389 Chapter 18: Gas-Liquid Equilibria 391 18.1 Introduction 391 18.2 Raoult's Law and Henry's Law 391 18.3 Equilibrium Calculations Involving Gas-Liquid Equilibria 398 18.4 Dissolved Carbon Dioxide 405 18.5 Summary 410 18.6 Part V Case Study: The Killer Lakes 410 ; Summary of Key Ideas 412 Problems 413 Chapter 19: Solid-Liquid Equilibria and the Aquatic Chemistry of Surfaces 417 19.1 Introduction 417 19.2 Saturation and the Activity of Pure Solids 417 19.3 Equilibrium Calculations Involving Solid-Liquid Equilibria 420 19.4 Factors Affecting Metal Solubility 428 19.5 Solubility of Calcium Carbonate 433 19.6 Summary of the Acid-Base Chemistry of Natural Waters 437 19.7 Aquatic Chemistry of Surfaces 443 19.8 Summary 450 19.9 Part V Case Study: The Killer Lakes 451 Summary of Key Ideas 452 Problems 453
Xlll Part VI: Beyond DttuteJSyjftejns^^ Chapter 20: Getting Started with Beyond Dilute Systems at Equilibrium 461 20.1 Introduction ~ 461 20.2 Extensions to Nonideal and Nonstandard Conditions 461 20.3 Nonequilibrium Conditions 464 20.4 Integrated Case Studies 465 20.5 Part VI Road Map 465 20.6 Summary 466 Summary of Key Ideas 466 Chapter 21: Thermodynamics Revisited 467 21.1 Introduction 467 21.2 Effects of Ionic Strength 468 21.3 Effects of Temperature on Chemical Equilibria 479 21.4 Effects of Pressure on Equilibrium Constants 484 21.5 Summary 486 Summary of Key Ideas 487 Historical Note: Jacobus Henricus Van't Hoff 488 Problems 488 Chapter 22: Chemical Kinetics of Aquatic Systems 491 22.1 Introduction 491 22.2 The Need for Chemical Kinetics 492 22.3 Reaction Rates 494 22.4 Common Rate Expressions 500 22.5 More Complex Kinetic Forms 506 22.6 Effects of Temperature and Ionic Strength on Reaction Kinetics 511 22.7 Summary 514 Summary of Key Ideas 515 Problems '516 Chapter 23: Putting It All Together: Integrated Chemistry of Aquatic Systems 519 23.1 Introduction 519 23.2 Integrated Case Study 1: Metal Finishing 519 23.3 Integrated Case Study 2: Oxidation of Ferrous Iron by Oxygen 524 23.4 Integrated Case Study 3: Inorganic Mercury Chemistry in Natural Waters 529 23.5 Summary 535 Appendix A: Background Information 537 A.I Introduction 537 A.2 Chemical Principles 537 A.3 Mathematical Principles 540 A.4 Computer Skills 540 Summary of Key Ideas 542 Appendix B: Equilibrium and Steady State 543 B.I Introduction 543 B.2 Steady-State Analysis 543 : J
XIV B.3 Comparison of Steady State and Equilibrium Solutions 544 Summary of Key Ideas 545 Appendix C: Summary of Procedures 547 C.I Oxidation State and Balancing Reactions 547 C.2 Setting Up Chemical Equilibrium Systems (section 6.4) 548 C.3 Algebraic Solution Techniques 549 C.4 Graphical Solutions 549 C.5 Computer Solutions: Tableau Method 552 C.6 Acid-Base Titrations 553 C.7 Complexation (section 15.4.4) 553 C.8 Ionic Strength Effects (section 21.2.7) 554 C.9 Chemical Kinetics (section 22.3.4) 554 Appendix D: Selected Chemical Equilibrium Constants 555 Appendix E: Animations and Example Computer Files 567 E.I Animations 567 E.2 Variation of Equilibrium ph of a Monoprotic Acid Solution with Total Acid Concentration and K a 567 E.3 How to Draw a pc-ph Diagram 569 E.4 Equilibrium ph During the Titration of a Monoprotic Acid with a Strong Base 570 E.5 Other Computer Files 571 Appendix F: Nanoql (also on CD) 573 F.I Installation 573 F.2 Using and Manipulating Files in Nanoql 573 F.3 Tips on Using Nonoql 575 References 577 Index 581