Discovering Design With Chemistry

Discovering Design With Chemistry Table of Contents Chapter 1: Measuring Up ............................................................................
Author: Clara Robinson
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Discovering Design With Chemistry Table of Contents

Chapter 1: Measuring Up ............................................................................................. 1 Introduction ........................................................................................................... 1 Measuring Distance ............................................................................................... 1 Using Different Units ........................................................................................... 2 Significant Figures ................................................................................................. 4 Using Significant Figures in Mathematical Problems....................................... 6 A Relationship Between Units............................................................................. 8 Experiment 1.1: Determining the Relationship Between in and cm ............ 8 Converting Between Units ................................................................................... 9 Prefixes in the Metric System ............................................................................ 11 Scientific Notation............................................................................................... 13 Measuring Area and Volume: Derived Units .................................................. 15 Experiment 1.2: Determining the Relationship Between cm3 and mL ...... 17 Converting Between Volume Units .................................................................. 18 Measuring Mass.................................................................................................... 19 Measuring Time ................................................................................................... 22 Density .................................................................................................................. 22 More on Density .................................................................................................. 25 Experiment 1.3: Density .................................................................................... 25 Solutions to the “Comprehension Check” Questions ................................... 27 Sample Calculations for Experiment 1.1.......................................................... 32 Sample Calculations for Experiment 1.2.......................................................... 32 Sample Calculations for Experiment 1.3.......................................................... 33 Review ................................................................................................................... 34 Chapter 2: What’s The Matter? ................................................................................. 37 Introduction ......................................................................................................... 37 Mixtures and Pure Substances ........................................................................... 37 Experiment 2.1: Separating a Mixture of Salt and Chervil ........................... 38 Homogeneous and Heterogeneous Mixtures .................................................. 40 Mass Conservation: It’s Not Just a Good Idea, It’s the Law! ....................... 42 Experiment 2.2: The Conservation of Mass................................................... 42 Elements and Compounds ................................................................................. 44 The Law of Definite Proportions ..................................................................... 47 Experiment 2.3: Oh What a Difference Some Oxygen Makes ................... 47 Dalton’s Atomic Theory ..................................................................................... 51 The Law of Multiple Proportions ..................................................................... 53 What’s Wrong with Dalton’s Theory: Part One ............................................ 54 What’s Wrong with Dalton’s Theory: Part Two ............................................ 58 Solutions to the “Comprehension Check” Questions ................................... 61 Review ................................................................................................................... 64

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Chapter 3: Making Sense of Atoms and Elements................................................. 67 Introduction .......................................................................................................... 67 Abbreviating and Arranging Elements ............................................................. 67 The Periodic Table of the Elements ................................................................. 68 Defining the Atoms that Make Up an Element .............................................. 70 Isotopes, Radiation, and Nuclear Weapons ..................................................... 73 Light Waves .......................................................................................................... 75 The Electromagnetic Spectrum ......................................................................... 78 Experiment 3.1: The Wavelength of Microwaves .......................................... 79 The Energy of Light ............................................................................................ 81 Illuminating the Structure of Atoms: The Bohr Model .................................. 82 Experiment 3.2: Flame Tests............................................................................. 83 More on The Bohr Model................................................................................... 87 Spectroscopy ......................................................................................................... 89 Solutions to the “Comprehension Check” Questions .................................... 91 Sample Calculations for Experiment 3.1 .......................................................... 94 Review.................................................................................................................... 95

Chapter 4: The Modern View of Atoms and Their Chemistry ........................... 97 Introduction .......................................................................................................... 97 Waves, Particles, or Both?................................................................................... 97 Experiment 4.1: Interfering Light ...................................................................... 97 Out with Orbits, In with Orbitals ....................................................................100 Wait a Minute – Do Electrons Really Behave Like Waves? ........................104 So Where Do You Put These Electrons? .......................................................105 What Good Are Electron Configurations? ....................................................108 Lewis Structures for Elements .........................................................................110 Metals, Nonmetals, and the In-Betweens .......................................................112 Experiment 4.2: Comparing a Metal and a Nonmetal ..................................112 Ionic Compounds ..............................................................................................114 Ionic Compounds that Don’t Follow the Rules ............................................117 An Important Characteristic of Ionic Compounds.......................................118 Experiment 4.3: Electrolytes and Nonelectrolytes........................................118 Solutions to the “Comprehension Check” Questions ..................................121 Review..................................................................................................................124

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Chapter 5: Covalent Compounds and Their Molecular Geometry ................... 127 Introduction ....................................................................................................... 127 Share and Share Alike ....................................................................................... 127 Lewis Structures of Covalent Compounds .................................................... 129 More Complicated Lewis Structures............................................................... 131 Naming Covalent Compounds ........................................................................ 134 Periodic Properties and How They Affect Covalent Compounds ............ 136 A Consequence of Polar Covalent Bonds ..................................................... 139 Experiment 5.1: Bending Water ...................................................................... 139 Molecules in Three Dimensions ...................................................................... 143 Is It Polar?........................................................................................................... 148 Why Is Polarity Important? .............................................................................. 151 Experiment 5.2: Polar and Nonpolar ............................................................. 151 Solutions to the “Comprehension Check” Questions ................................. 154 Review ................................................................................................................. 159

Chapter 6: Physical and Chemical Change ............................................................ 161 Introduction ....................................................................................................... 161 Chemical and Physical Changes ...................................................................... 161 Temperature Changes ....................................................................................... 162 Phase Changes ................................................................................................... 164 Experiment 6.1: Cool it! ................................................................................... 165 The Kinetic Theory of Matter ......................................................................... 167 Experiment 6.2: In Between and All Around ............................................... 167 An Important Exception: Water ..................................................................... 171 Chemical Reactions ........................................................................................... 172 Balancing Chemical Equations ........................................................................ 176 The Mathematical Nature of Chemical Equations ....................................... 180 Formation and Decomposition Reactions..................................................... 181 Single and Double Displacement Reactions.................................................. 183 Experiment 6.3: Copper-Plated Nails............................................................. 183 Combustion Reactions...................................................................................... 185 Experiment 6.4: Burning Iron ......................................................................... 185 Solutions to the “Comprehension Check” Questions ................................. 189 Review ................................................................................................................. 195

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Chapter 7: Stoichiometry .......................................................................................... 197 Introduction ........................................................................................................197 Counting Atoms .................................................................................................197 Mole Problems – Not Just in Your Backyard ................................................199 Using the Mole Concept ...................................................................................201 Experiment 7.1: How “Wet” Is Hydrated Copper Sulfate?.........................202 Moles Infesting Chemical Equations ..............................................................204 There is a Limit! ..................................................................................................206 Experiment 7.2: The Limiting Reactant..........................................................206 Using More Complicated Chemical Equations .............................................209 Stoichiometry Gets Massive .............................................................................212 A Practical Application of Stoichiometry .......................................................216 Experiment 7.3: The Amount of NaHCO3 in Alka-Seltzer ........................216 Solutions to the “Comprehension Check” Questions ..................................218 Sample Calculations for Experiment 7.1 ........................................................222 Sample Calculations for Experiment 7.3 ........................................................223 Review..................................................................................................................224

Chapter 8: Still More on Stoichiometry ................................................................. 227 Introduction ........................................................................................................227 To Err is Human ................................................................................................227 Experiment 8.1: Percent Yield .........................................................................227 Percent Yield .......................................................................................................230 Empirical and Molecular Formulas .................................................................232 Determining Empirical Formulas of Metal Oxides ......................................235 Determining Empirical Formulas With Combustion Analysis ...................237 More complicated Combustion Analysis ........................................................239 Determining Empirical Formulas from Percent Composition ...................241 Polyatomic Ions ..................................................................................................243 Solutions to the “Comprehension Check” Questions ..................................248 Sample Calculations for Experiment 8.1 ........................................................253 Review..................................................................................................................254

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Chapter 9: Chemists Have Solutions .......................................................................257 Introduction ....................................................................................................... 257 Dissolving Solutes into Solvents ..................................................................... 257 Solubility ............................................................................................................. 260 Experiment 9.1: Temperature and Solubility................................................. 260 Some Ionic and Polar Covalent Chemicals Aren’t Very Soluble ............... 263 Experiment 9.2: Forming a Precipitate .......................................................... 264 Concentration..................................................................................................... 266 Experiment 9.3: The Importance of Concentration .................................... 266 Molarity ............................................................................................................... 269 Using Molarity in Stoichiometry ..................................................................... 270 Molality: Another Unit for Concentration ..................................................... 272 This is Depressing! ............................................................................................ 274 Experiment 9.4: Freezing Point Depression ................................................. 274 From Depressing to Elevating ........................................................................ 278 Solutions to the “Comprehension Check” Questions ................................. 280 Review ................................................................................................................. 286 Chapter 10: It’s a Gas! ................................................................................................. 289 Introduction ....................................................................................................... 289 How Pressure is Defined .................................................................................. 289 Boyle’s Law ......................................................................................................... 291 Experiment 10.1: Boyle’s Law ......................................................................... 292 Charles’s Law ..................................................................................................... 294 Experiment 10.2: Charles’s Law ...................................................................... 294 Charles’s Law and Absolute Temperature ..................................................... 295 The Combined Gas Law .................................................................................. 298 It’s Got To Be Ideal! ......................................................................................... 300 This Law Is Ideal! .............................................................................................. 301 Gases in Stoichiometry ..................................................................................... 304 Dalton’s Law of Partial Pressures ................................................................... 306 Vapor Pressure and Boiling Point ................................................................... 310 Experiment 10.3: Boiling Water with Ice....................................................... 312 Vapor Pressure and Dalton’s Law .................................................................. 313 Experiment 10.4: The Concentration of Hydrogen Peroxide .................... 314 Solutions to the “Comprehension Check” Questions ................................. 317 Sample Calculations for Experiment 10.4 ..................................................... 322 Review ................................................................................................................. 323

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Chapter 11: Some Pretty Basic (and Acidic) Chemicals ..................................... 325 Introduction ........................................................................................................325 Characteristics of Acids and Bases ..................................................................325 Experiment 11.1: Litmus Tests ........................................................................327 The Chemical Definition of Acids and Bases ................................................329 Acids and Ionic Bases ........................................................................................332 Sometimes, You Can Just Tell..........................................................................333 Determining The Chemical Equation for an Acid/Base Reaction.............335 The pH Scale.......................................................................................................337 Experiment 11.2: Anthocyanins as Acid/Base Indicators ...........................339 Acid/Base Neutralization .................................................................................341 Acid/Base Titrations .........................................................................................343 Experiment 11.3: The Percent of Acetic Acid in Vinegar ...........................345 Diluting Acids and Bases ..................................................................................347 Solutions to the “Comprehension Check” Questions ..................................349 Sample Calculations for Experiment 11.3 ......................................................353 Review..................................................................................................................354 Chapter 12: Reduction and Oxidation.................................................................... 357 Introduction ........................................................................................................357 Oxidation States .................................................................................................357 Determining Oxidation States ..........................................................................360 Reduction and Oxidation ..................................................................................363 Experiment 12.1: Oxidation States of Iron ....................................................366 The Basics of Batteries ......................................................................................368 Experiment 12.2: A Simple Galvanic Cell ......................................................368 Analyzing Galvanic Cells ..................................................................................372 Counting Electrons and Balancing Simple Redox Equations .....................374 Batteries That You Actually Use ......................................................................376 Electroplating......................................................................................................378 Experiment 12.3: Electroplating ......................................................................378 The Downside of Redox Reactions.................................................................380 Solutions to the “Comprehension Check” Questions ..................................381 Review..................................................................................................................385

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Chapter 13: The Heat is On ........................................................................................387 Introduction ....................................................................................................... 387 What is Heat? ..................................................................................................... 387 Calories, calories, and Joules ............................................................................ 389 Specific Heat Capacity ...................................................................................... 391 Experiment 13.1: Specific Heat Capacity....................................................... 391 Measuring Heat .................................................................................................. 393 Calorimetry ......................................................................................................... 395 Experiment 13.2: A Calorimetry Experiment ............................................... 397 More Detailed Calorimetry Experiments ....................................................... 400 Latent Heat ......................................................................................................... 402 Experiment 13.3: Melting Ice .......................................................................... 403 The Heat Associated with Chemical Reactions ............................................ 406 Experiment 13.4: An Endothermic Reaction ................................................ 407 Solutions to the “Comprehension Check” Questions ................................. 409 Sample Calculations for Experiment 13.2 ..................................................... 414 Review ................................................................................................................. 415 Chapter 14: Thermodynamics ................................................................................... 417 Introduction ....................................................................................................... 417 Enthalpy .............................................................................................................. 417 Experiment 14.1: Measuring ∆H..................................................................... 418 Enthalpy Change and Bond Energies ............................................................ 419 Enthalpy Change and Hess’s Law ................................................................... 422 Enthalpy and Stoichiometry ............................................................................ 426 Activation Energy .............................................................................................. 427 Thermodynamics ............................................................................................... 430 Changes in Entropy........................................................................................... 434 Getting Numbers for ∆S .................................................................................. 437 The Gibbs Free Energy .................................................................................... 439 Experiment 14.2: Determining ∆S for a Physical Change .......................... 442 The Gibbs Free Energy and Hess’s Law ....................................................... 443 Solutions to the “Comprehension Check” Questions ................................. 446 Sample Calculations for Experiment 14.1 ..................................................... 450 Review ................................................................................................................. 451

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Chapter 15: Kinetics ................................................................................................... 453 Introduction ........................................................................................................453 Rate Your Reactions ..........................................................................................454 What Things Affect the Rate of a Chemical Reaction? ................................455 Experiment 15.1: Changing the Rate of a Reaction ......................................455 Collision Theory .................................................................................................457 The Rate Equation .............................................................................................459 It Lasts Only for an Instant ..............................................................................461 Determining Reaction Orders ..........................................................................462 Activation Energy, Temperature, and the Rate Constant ............................467 Catalysts ...............................................................................................................469 Experiment 15.2: Catalysts Don’t Get Used Up ...........................................469 How Catalysts Work ..........................................................................................471 Solutions to the “Comprehension Check” Questions ..................................476 Review..................................................................................................................481 Chapter 16: Chemical Equilibrium .......................................................................... 483 Introduction ........................................................................................................483 Establishing Chemical Equilibrium .................................................................484 Experiment 16.1: Water in Equilibrium .........................................................484 The Equilibrium Constant ................................................................................486 The Chemical Meaning of the Equilibrium Constant ..................................488 Ignoring Things ..................................................................................................490 Are We There Yet? ............................................................................................492 Why Salt Melts Ice .............................................................................................494 This is Disturbing ...............................................................................................495 More on Le Chatelier’s Principle .....................................................................497 Experiment 16.2: Le Chatelier’s Principle and Concentration ....................497 Le Chatelier’s Principle and Temperature ......................................................500 Experiment 16.3: Le Chatelier’s Principle and Temperature.......................501 Le Chatelier’s Principle and Pressure ..............................................................503 Equilibrium Concepts Applied to Acids and Bases ......................................504 All Good Things Must Come to an End ........................................................507 Solutions to the “Comprehension Check” Questions ..................................508 Review..................................................................................................................511 Appendix A.................................................................................................................................... 513 Appendix B .................................................................................................................................... 519 Appendix C ..................................................................................................................................... 527 Glossary ............................................................................................................................................ 533 Photo/Illustration Credits ...................................................................................................... 542 Index .................................................................................................................................................. 543 xviii