Exploring Chemical Analysis , Fourth Edition

Cover Page......Page 1
Title Page
......Page 5
Copyright Page
......Page 6
Contents......Page 7
Problem Solving......Page 13
The People......Page 14
Acknowledgments......Page 15
0-1 The Analytical Chemist’s Job......Page 17
Sample Preparation......Page 18
The Chemical Analysis (At Last!)......Page 20
Calibration Curves......Page 21
Interpreting the Results......Page 22
Quality Assurance......Page 23
0-2 General Steps in a Chemical Analysis......Page 25
0-3 Charles David Keeling and the Measurement of Atmospheric CO2......Page 26
1-1 SI Units and Prefixes......Page 35
1-2 Conversion Between Units......Page 39
Molarity and Molality......Page 41
Percent Composition......Page 43
Parts per Million and Parts per Billion......Page 44
1-4 Preparing Solutions......Page 45
1-5 The Equilibrium Constant......Page 49
Manipulating Equilibrium Constants......Page 50
Le Châtelier’s Principle......Page 51
2-1 Safety, Waste Disposal, and Green Chemistry......Page 57
2-2 Your Lab Notebook......Page 58
2-3 The Analytical Balance......Page 59
Buoyancy......Page 61
2-4 Burets......Page 62
2-5 Volumetric Flasks......Page 64
Micropipets......Page 66
2-7 Filtration......Page 68
2-8 Drying......Page 69
2-10 Methods of Sample Preparation......Page 70
Fusion 
......Page 71
Extraction......Page 72
Reference Procedure: Calibrating a 50-mL Buret......Page 73
3-1 Significant Figures......Page 77
Addition and Subtraction......Page 78
Multiplication and Division......Page 79
Logarithms and Antilogarithms......Page 80
Systematic Error 
......Page 81
Absolute and Relative Uncertainty......Page 84
Addition and Subtraction......Page 85
Multiplication and Division......Page 86
The Real Rule for Significant Figures......Page 88
A Spreadsheet for Temperature Conversions......Page 90
Documentation and Readability......Page 92
3-6 Graphing in Excel......Page 93
4-1 The Gaussian Distribution......Page 99
Mean and Standard Deviation......Page 100
Confidence Intervals......Page 102
Comparison of Means with Student’s t......Page 104
4-3 A Spreadsheet for the t Test......Page 106
4-4 Grubbs Test for an Outlier......Page 108
Method of Least Squares 
......Page 109
How Reliable Are Least-Squares Parameters?......Page 111
4-6 Constructing a Calibration Curve......Page 112
Finding the Protein in an Unknown......Page 113
4-7 A Spreadsheet for Least Squares......Page 114
Adding Error Bars to a Graph......Page 116
Use Objectives......Page 123
Specifications......Page 124
Assessment......Page 126
Limits of Detection and Quantitation......Page 128
5-3 Standard Addition......Page 131
Graphical Procedure for Standard Addition......Page 133
5-4 Internal Standards......Page 135
6-1 Principles of Volumetric Analysis......Page 143
1:1 Stoichiometry......Page 146
x :y Stoichiometry 
......Page 147
6-3 Chemistry in a Fishtank......Page 148
Calculating the Solubility of an Ionic Compound......Page 152
The Common Ion Effect......Page 153
6-5 Titration of a Mixture......Page 156
6-6 Titrations Involving Silver Ion......Page 158
Fajans Titration......Page 159
7-1 Examples of Gravimetric Analysis......Page 167
7-2 Precipitation......Page 169
Homogeneous Precipitation......Page 171
Precipitation in the Presence of Electrolyte......Page 172
Purity......Page 174
Product Composition......Page 175
7-3 Examples of Gravimetric Calculations......Page 176
Gravimetric Combustion Analysis......Page 180
Combustion Analysis Today......Page 181
8-1 What Are Acids and Bases?......Page 187
8-2 Relation Between [H+], [OH- ], and pH......Page 188
8-3 Strengths of Acids and Bases......Page 190
Carboxylic Acids Are Weak Acids and Amines Are  Weak Bases......Page 191
Metal Ions with Charge ≥ 2 Are Weak Acids......Page 193
Relation Between Ka and Kb......Page 194
pH of a Strong Acid......Page 195
pH of a Strong Base......Page 196
Weak Is Conjugate to Weak......Page 197
8-6 Weak-Acid Equilibrium......Page 198
Fraction of Dissociation......Page 200
The Essence of a Weak-Acid Problem 
......Page 201
8-7 Weak-Base Equilibrium......Page 202
Conjugate Acids and Bases—Revisited......Page 204
9-1 What You Mix Is What You Get......Page 211
9-2 The Henderson-Hasselbalch Equation......Page 212
When [A-]/[HA] Changes by a Factor of 10,the pH Changes by One Unit......Page 213
9-3 A Buffer in Action......Page 214
9-4 Preparing Buffers......Page 217
Preparing a Buffer in Real Life......Page 218
9-5 Buffer Capacity......Page 219
9-6 How Acid-Base Indicators Work......Page 222
10-1 Titration of Strong Base with Strong Acid......Page 229
10-2 Titration of Weak Acid with Strong Base......Page 232
The Titration Curve......Page 235
10-3 Titration of Weak Base with Strong Acid......Page 236
Using Indicators to Find the End Point......Page 238
Using a pH Electrode to Find the End Point 
......Page 239
10-5 Practical Notes......Page 243
10-6 Kjeldahl Nitrogen Analysis......Page 244
Titrating a Weak Acid with a Strong Base......Page 246
Titrating a Weak Base with a Strong Acid......Page 248
Reference Procedure: Preparing standard acid and base......Page 252
11-1 Amino Acids Are Polyprotic......Page 255
Relation Between Ka and Kb......Page 257
11-2 Finding the pH in Diprotic Systems......Page 258
The Basic Form, L-......Page 259
The Intermediate Form, HL......Page 262
Summary of Diprotic Acid Calculations
......Page 264
11-3 Which Is the Principal Species?......Page 265
11-4 Titrations in Polyprotic Systems......Page 268
Proteins Are Polyprotic Acids and Bases......Page 272
12-1 The Effect of Ionic Strength on Solubility of Salts......Page 281
What Do We Mean by “Ionic Strength”?......Page 282
12-2 Activity Coefficients......Page 283
Activity Coefficients of Ions......Page 284
How to Interpolate......Page 286
Activity Coefficients of Nonionic Compounds......Page 287
High Ionic Strengths......Page 288
The Real Definition of pH......Page 289
Charge Balance......Page 290
Mass Balance......Page 291
12-4 Systematic Treatment of Equilibrium......Page 292
Coupled Equilibria: Solubility of CaF[sub(2)]......Page 293
12-5 Fractional Composition Equations......Page 295
13-1 Metal-Chelate Complexes......Page 303
13-2 EDTA......Page 306
13-3 Metal Ion Indicators......Page 309
Back Titration......Page 311
Indirect Titration......Page 312
Masking......Page 313
Fractional Composition of EDTA Solutions......Page 314
Conditional Formation Constant 
......Page 315
13-6 EDTA Titration Curves......Page 317
Titration Calculations......Page 318
Beware......Page 319
Chemistry and Electricity 
......Page 325
Electric Current Is Proportional to the Rate of a Redox Reaction......Page 326
Voltage and Electrical Work......Page 327
14-2 Galvanic Cells......Page 328
A Cell in Action......Page 329
Line Notation 
......Page 331
14-3 Standard Potentials......Page 332
What the Standard Potential Means......Page 334
14-4 The Nernst Equation......Page 335
Nernst Equation for a Half-Reaction......Page 336
Nernst Equation for a Complete Reaction......Page 337
Different Descriptions of the Same Reaction......Page 338
Advice for Finding Relevant Half-Reactions......Page 339
14-5 E° and the Equilibrium Constant......Page 340
Silver-Silver Chloride Reference Electrode 
......Page 343
Voltage Conversions Between Different Reference Scales......Page 344
15-1 The Silver Indicator Electrode......Page 351
Titration of a Halide Ion with Ag+......Page 352
Double-Junction Reference Electrode 
......Page 353
Direct Versus Relative Potentiometric Measurements 
......Page 355
15-3 How Ion-Selective Electrodes Work......Page 357
Two Classes of Indicator Electrodes......Page 358
15-4 pH Measurement with a Glass Electrode......Page 359
Errors in pH Measurement......Page 360
Solid-State pH Sensors......Page 362
Solid-State Electrodes 
......Page 363
Liquid-Based Ion-Selective Electrodes......Page 364
Selectivity Coefficient......Page 365
Compound Electrodes 
......Page 367
16-1 Theory of Redox Titrations......Page 373
Shapes of Redox Titration Curves 
......Page 377
16-2 Redox Indicators......Page 379
16-3 Titrations Involving Iodine......Page 380
Preparation and Standardization of I[sub(3)][sup(-)] Solutions......Page 382
Use of Sodium Thiosulfate......Page 384
Electrogravimetric Analysis......Page 389
Coulometric Analysis......Page 390
17-2 Amperometry......Page 392
Glucose Monitors......Page 393
Cells with Three Electrodes......Page 394
Amperometric Detector for Chromatography......Page 395
17-3 Voltammetry......Page 397
17-4 Polarography......Page 399
The Polarogram......Page 400
Square Wave Voltammetry......Page 401
Stripping Analysis......Page 402
18-1 Properties of Light......Page 409
Transmittance, Absorbance, and Beer’s Law......Page 412
Absorption Spectra and Color......Page 416
18-3 Practical Matters......Page 418
Good Operating Techniques......Page 419
18-4 Using Beer’s Law......Page 420
Using a Standard Curve to Measure Nitrite......Page 422
Enzyme-Based Nitrate Analysis—A Green Idea......Page 424
19-1 The Spectrophotometer......Page 431
Light Source......Page 432
Monochromator......Page 433
Detector......Page 435
Photodiode Array Spectrophotometer......Page 436
19-2 Analysis of a Mixture......Page 437
Isosbestic Points......Page 439
19-3 Spectrophotometric Titrations......Page 440
Electronic States of Formaldehyde
......Page 441
What Happens to Absorbed Energy? 
......Page 443
19-5 Luminescence in Analytical Chemistry......Page 446
Fluorimetric Assay of Selenium in Brazil Nuts......Page 447
Immunoassays......Page 448
20-1 What Is Atomic Spectroscopy?......Page 457
20-2 Atomization: Flames, Furnaces, and Plasmas......Page 458
Furnace......Page 459
Detection Limits......Page 461
The Effect of Temperature on Absorption and Emission......Page 463
Hollow-Cathode Lamps......Page 464
Background Correction 
......Page 465
Multielement Analysis with the Inductively Coupled Plasma......Page 466
Types of Interference 
......Page 467
Virtues of the Inductively Coupled Plasma......Page 468
20-6 Inductively Coupled Plasma– Mass Spectrometry......Page 469
21-1 What Is Chromatography?......Page 475
21-2 How We Describe a Chromatogram......Page 477
Theoretical Plates......Page 478
Resolution......Page 479
Scaling Up a Separation......Page 480
Bands Diffuse 
......Page 481
Plate Height Equation......Page 482
Open Tubular Columns......Page 483
21-4 Mass Spectrometry......Page 485
A Mass Spectrometer......Page 486
Ionization......Page 487
Total Ion and Selected Ion Chromatograms......Page 488
Fragmentation Patterns 
......Page 489
Isotope Patterns and the Nitrogen Rule......Page 490
22-1 Gas Chromatography......Page 497
Columns......Page 498
Temperature Programming......Page 501
Sample Injection......Page 502
Flame Ionization Detector......Page 503
Other Detectors......Page 504
Mass Spectrometric Detection and Selected Reaction Monitoring......Page 505
Solvents......Page 507
22-3 High-Performance Liquid Chromatography......Page 508
Stationary Phase......Page 510
The Column 
......Page 511
Detectors......Page 513
Liquid Chromatography–Mass Spectrometry......Page 515
22-4 Sample Preparation for Chromatography......Page 517
23-1 Ion-Exchange Chromatography......Page 527
Ion-Exchange Selectivity......Page 528
Preconcentration......Page 530
23-2 Ion Chromatography 515......Page 531
23-3 Molecular Exclusion Chromatography......Page 532
Molecular Mass Determination 
......Page 533
23-4 Affinity Chromatography......Page 534
23-5 What Is Capillary Electrophoresis?......Page 535
Electroosmosis......Page 537
Detectors......Page 538
23-7 Types of Capillary Electrophoresis......Page 539
Micellar Electrokinetic Capillary Chromatography......Page 540
Capillary Gel Electrophoresis......Page 541
23-8 Lab on a Chip: Probing Brain Chemistry......Page 543
Appendix A
......Page 549
Appendix B
......Page 551
Appendix C
......Page 559
Appendix D
......Page 563
Glossary......Page 566
Solutions to “Ask Yourself ”Questions......Page 583
Answers to Problems......Page 604
Index......Page 613