Introduction to chemical principles

FLFVFNTH EDITION

INTRODUCTION TO

CH EM1CAL
PRINCIPLES
H. STEPHEN STOKER


www.pdfgrip.com

Periodic Table of the Elements
18
Group
VIIIA

1
Group
1A

1

2
Group
IIA

13
Group
IIIA

14

Group
IVA

15
Group
VA

17
Group
VIIA

4

5

6

7

16
Group
VIA
8

Li

Be

c

N

o

F

Ne

6.94
11

9.01
12

B
10.81

12.01
14

14.01
15

16.00
16

19.00
17

20.18

18

Na

Mg

22.99
19

24.31
20

23

24

25

26

27

28

29

-

K

Ca

Sc

Ti

V

Cr

Mn

Fe

Co

Ni

Cu

Zn

Ga

Ge

As

Se

Br

Kr

39.10

40.08

47.87

50.94

54.94

55.85

58.93

63.55
47

65.38

69.72

72.63

74.92

79.90

83.80
54

11
1.01
3

4
Group
IVB

3
Group
II1B
21

5
Group
VB

6
Group
VIB

7
Group
VIIB

8

9
Group
Group
-------- V11IB

10
Group
-------- ►

11
Group
IB

12
Group
I1B

9

He

4.00
10

Al

Si

P

s

Cl

Ar

26.98
31

28.09

30.97
33

32.06
34

35.45
35

39.95
36

37

38

44.96
39

40

41

52.00
42

43

44

45

58.69
46

48

49

50

51

78.96
52

Rb

Sr

Y

Zr

Nb

Mo

Tc

Ru

Rh

Pd

Ag

Cd

In

Sn

Sb

Te

I

Xe

85.47
55

87.62
56

88.91

9122
72

92.91
73

95.96
74

(98)
75

101.07
76

102.91
77

106.42

78

107.87
79

112.41
80

114.82
81

118.71
82

121.76
83

127.60
84

126.90
85

131.29
86

Cs

Ba

La

Hf

Ta

w

Re

Os

It

Pt

Au

Hg

Tl

Pb

Bi

Po

At

Rn

132.91
87

13733
88

138.91
89

178.49
104

180.95
105

183.84
106

186.21
107

190.23
108

192.22
109

195.08

110

196.97
111

200.59
112

204.38
113

207.2
114

208.98
115

(209)
116

(210)
117

(222)
118

Ac

Rf

(227) |

Db

sg

Bh

Hs

Mt

Ds

Rg

Cn

—

Fl

—

Lv

—

—

(268)

(271)

(272)

(270)

(276)

(281)

(280)

(285)

(284)

(289)

(288)

(293)

(293)

(294)

Nonmetals

Metals
58

59

60

61

62

63

64

65

66

67

68

69

70

71

Ce

Pr

Nd

Pm

Sm

Eu

Gd

Tb

Dy

Ho

Er

Yb

Lu

140.12
90
Th

140.91

91
Pa

144.24

(145)
93
Np

150.36
94
Pu

151.96
95
Am

15725
96
Cm

158.93
97
Bk

162.50
98
Cf

164.93

99
Es

167.26
100
Fm

1 111
168.93
101
Md

173.05
102
No

174.97
103
Lr

232.04

231.04

(237)

(244)

(243)

(247)

(247)

(251)

(252)

(257)

(258)

(259)

(262)

i es

Ra
(226)

1

£

Fr
(223)

57

53


www.pdfgrip.com

LIST OF ELEMENTS WITH THEIR SYMBOLS AND ATOMIC MASSES
Element

Actinium
Aluminum
Americium
Antimony
Argon
Arsenic
Astatine
Barium
Berkelium
Beryllium
Bismuth
Bohrium
Boron
Bromine
Cadmium
Calcium
Californium
Carbon
Cerium
Cesium
Chlorine
Chromium

Cobalt
Copernicium
Copper
Curium
Darmstadtium
Dubnium
Dysprosium
Einsteinium
Erbium
Europium
Fermium
Flerovium
Fluorine
Francium
Gadolinium
Gallium
Germanium
Gold
Hafnium
Hassium
Helium
Holmium
Hydrogen
Indium
Iodine
Iridium
Iron
Krypton
Lanthanum
Lawrencium

Lead
Lithium
Lutetium
Livermorium
Magnesium
Manganese
Meitnerium

Symbol

Atomic
Number

Atomic
Mass

Ac
Al
Am
Sb
Ar
As
At
Ba
Bk
Be
Bi
Bh
B
Br

Cd
Ca
Cf
C
Ce
Cs
Cl
Cr
Co
Cn
Cu
Cm
Ds
Db
Dy
Es
Er
Eu
Fm
Fl
F
Fr
Gd
Ga
Ge
Au
Hf
Hs
He
Ho

H
In
1
Ir
Fe
Kr
La
Lr
Pb
Li
Lu
Lv
Mg
Mn
Mt

89
13
95
51
18
33
85
56
97
4
83
107
5
35

48
20
98
6
58
55
17
24
27
112
29
96
110
105
66
99
68
63
100
114
9
87
64
31
32
79
72
108
2
67

1
49
53
77
26
36
57
103
82
3
71
116
12
25
109

(227)
26.98
(243)
121.76
39.95
74.92
(210)
137.33
(247)
9.012
208.98
(272)
10.81
79.90

112.41
40.08
(251)
12.01
140.12
132.91
35.45
52.00
58.93
(285)
63.55
(247)
(281)
(268)
162.50
(252)
167.26
151.96
(257)
(289)
19.00
(223)
157.25
69.72
72.63
196.97
178.49
(270)
4.003
164.93

1.008
114.82
126.90
192.22
55.85
83.80
138.91
(262)
207.2
6.941
174.97
(293)
24.31
54.94
(276)

Element

Mendelevium
Mercury
Molybdenum
Neodymium
Neon
Neptunium
Nickel
Niobium
Nitrogen
Nobelium
Osmium
Oxygen

Palladium
Phosphorus
Platinum
Plutonium
Polonium
Potassium
Praseodymium
Promethium
Protactinium
Radium
Radon
Rhenium
Rhodium
Roentgenium
Rubidium
Ruthenium
Rutherfordium
Samarium
Scandium
Seaborgium
Selenium
Silicon
Silver
Sodium
Strontium
Sulfur
Tantalum
Technetium
Tellurium
Terbium

Thallium
Thorium
Thulium
Tin
Titanium
Tungsten
Uranium
Vanadium
Xenon
Ytterbium
Yttrium
Zinc
Zirconium
Element 113
Element 115
Element 117
Element 118

Symbol

Atomic
Number

Md
Hg
Mo
Nd
Ne
Np
Ni

Nb
N
No
Os
O
Pd
P
Pt
Pu
Po
K
Pr
Pm
Pa
Ra
Rn
Re
Rh
Rg
Rb
Ru
Rf
Sm
Sc
Sg
Se
Si
Ag
Na
Sr

S
Ta
Tc
Te
Tb
n
Th
Tm
Sn
Ti
W
U
V
Xe
Yb
Y
Zn
Zr
—
—
—
—

101
80
42
60
10
93
28

41
7
102
76
8
46
15
78
94
84
19
59
61
91
88
86
75
45
111
37
44
104
62
21
106
34
14
47
11
38

16
73
43
52
65
81
90
69
50
22
74
92
23
54
70
39
30
40
113
115
117
118

Atomic
Mass
(258)
200.59
95.94
144.24
20.18

(237)
58.69
92.91
14.01
(259)
190.23
16.00
106.42
30.97
195.08
(244)
(209)
39.10
140.91
(145)
231.04
(226)
(222)
186.21
102.91
(280)
85.47
101.07
(267)
150.36
44.96
(271)
78.96
28.09
107.87

22.99
87.62
32.06
180.95
(98)
127.60
158.93
204.38
232.04
168.93
118.71
47.87
183.84
238.03
50.94
131.293
173.04
88.91
65.41
91.22
(284)
(288)
(293)
(294)

A mass value which is enclosed in parentheses is the mass number for the most stable isotope of an element that is laboratory produced rather than naturally
occurring.


www.pdfgrip.com

Eleventh Edition

Introduction to
Chemical Principles


www.pdfgrip.com

This page intentionally left blank


www.pdfgrip.com

Eleventh Edition

Introduction to
Chemical Principles
H. Stephen Stoker
Weber State University

PEARSON
Columbus Indianapolis New York San Francisco Upper Saddle River
Amsterdam Cape Town Dubai London .Madrid Milan Munich Paris Montreal Toronto
Delhi Mexico City Sao Paulo Sydney I long Kong Seoul Singapore Taipei Tokyo
Boston


www.pdfgrip.com

Editor in Chief: Adam Jaworski
Senior Marketing Manager: Jonathan Cottrell
Assistant Editor: Coleen Morrison
Editorial Assistant: Fran Falk
Marketing Assistant: Nicola Houston
Managing Editor, Chemistry and Geosciences: Gina M. Cheselka
Project Manager, Production: Connie Long
Full Service Project Management: Marie Desrosiers, PreMediaGlobal
Compositor: PreMediaGlobal
Text Permissions Manager: Joseph Croscup
Text Permissions Researcher: Jen Roach
Image Lead: Maya Melenchuk
Photo Researcher: Eric Schrader
Cover Designer: Seventeenth Street Studios
Operations Specialist: Jeffrey Sargent
Cover Image Credit: Shilova Ekaterina / Shutterstock

Credits and acknowledgments borrowed from other sources and reproduced, with permission, in this textbook
appear on the appropriate page within this book.

Copyright © 2014, 2011, 2008, 2005 Pearson Education. Inc. All rights reserved. Manufactured in the United
States of America. This publication is protected by Copyright, and permission should be obtained from the
publisher prior to any prohibited reproduction, storage in a retrieval system, or transmission in any form or by
any means: electronic, mechanical, photocopying, recording, or likewise. To obtain permission(s) to use
material from this work, please submit a written request to Pearson Education. Inc., Permissions Department.
1 Lake Street, Department 1G, Upper Saddle River. NJ 07458.
Many of the designations used by manufacturers and sellers to distinguish their products are claimed as
trademarks. Where those designations appear in this book, and the publisher was aware of a trademark claim,
the designations have been printed in initial caps or all caps.
Library of Congress Cataloging-in-Publication Data

Stoker, H. Stephen (Howard Stephen), 1939-

Introduction to chemical principles / H. Stephen Stoker. — 11th ed.
p. cm.
Includes index.
ISBN 978-0-321-81463-0
1. Chemistry. I. Title.
QD33-2.S76 2012
540—dc23
2012038211

12345 6 789 10—EB—16 15 14 13 12

PEARSON

www.pearsonhighered.com

ISBN-10: 0-321-81463-0: ISBN-13: 978-0-321-81463-0


www.pdfgrip.com

CONTENTS
Preface xiii
Acknowledgments xvi

Chapter 1

The Science of Chemistry
1.1

1.2
1.3
1.4

1

Chemistry—A Scientific Discipline

1

Scientific Research and Technology 3
The Scope of Chemistry 4
How Chemists Discover Things—The Scientific Method
Experiments, Observations, and Data 5

4

Scientific Facts 6
Scientific Laws 7
Scientific Hypotheses 7
Scientific Theories 8
1.5 The Limitations of the Scientific Method 10
1.6 Application Limitations for methods of Science 11
Concepts to Remember 11 • Key Terms Listing 12
Practice Problems By Topic 12 • Multiple-Choice Practice Test

Chapter 2

Numbers From Measurements

17

2.1 The Importance of Measurement

17

2.2
2.3
2.4
2.5

15

Exact and Inexact Numbers 18
Accuracy, Precision, and Error 18
Uncertainty in Measurements 20
Significant Figures 22

2.6 Significant Figures and Mathematical Operations 27
Rounding Off Numbers 27
Operational Rules for Mathematical Operations 29
Significant Figures and Exact Numbers 33
Multiplication by a Small Whole Number 33
2.7 Expressing Numbers in Scientific Notation 35
Exponents 36
Converting from Decimal to Scientific Notation 37
Significant Figures and Scientific Notation 38
Converting from Scientific to Decimal Notation 39
Uncertainty and Scientific Notation 40

2.8 Mathematical Operations in Scientific Notation 42
Multiplication in Scientific Notation 42
Division in Scientific Notation 44
Addition and Subtraction in Scientific Notation 45
Concepts to Remember 48 • Key Terms Listing 49
Practice Problems By Topic 49 • Multi-Concept Problems
Multiple Choice Practice Test 58

Chapter 3

Unit Systems and Dimensional Analysis
3.1 The Metric System of Units

60
SI Units 61
Metric System Prefixes 62
3.2 Metric Units of Length 63
3.3 Metric Units of Mass 64
3.4 Metric Units of Volume 65
3.5 Units in Mathematical Operations 68

60

57


www.pdfgrip.com

vi

Contents
Conversion Factors

3.6

68

English-to-English Conversion Factors
Metric-to-Metric Conversion Factors

69
69

Metric-to-English and English-to-Metric Conversion Factors
Dimensional Analysis

3.7

70

72
72

Metric-to-Metric Conversion Factor Use

English-to-English Conversion Factor Use

77

English-to-Metric and Metric-to-English Conversion Factor Use

Units Involving More Than One Type of Measurement

Density

3.8

82

83

Using Density as a Conversion Factor

86

Equivalence Conversion Factors Other than Density

3.9

88

Concentration and Dosage Relationship Conversion Factors
Rate Relationship Conversion Factors

89

Cost Relationship Conversion Factors

90

3.10

Percentage and Percent Error

Percent Error

88

91

Using Percentage as a Conversion Factor

3.11

78

92

95

Temperature Scales

96

Temperature Readings and Significant Figures 101
Concepts to Remember 101 • Key Terms Listing 102
Practice Problems By Topic 102 • Multi-Concept Problems
Multiple Choice Practice Test 109

Chapter 4

Basic Concepts About Matter

111

4.1

Chemistry—The Study of Matter

111

4.2

Physical States of Matter

4.3

Properties of Matter

112

113

Physical and Chemical Properties

114

Intensive and Extensive Properties
4.4

Changes in Matter

115

116

Use of the Terms Physical and Chemical

118

4.5

Pure Substances and Mixtures

4.6

Heterogeneous and Homogeneous Mixtures

119
120

Use of the Terms Homogeneous and Heterogeneous
4.7
4.8

Elements and Compounds

121

123

Discovery and Abundance of the Elements

126

■ THE HUMAN SIDE OF CHEMISTRY 1: Joseph Priestley (1733-1804)

4.9

108

Names and Chemical Symbols of the Elements

127

127

■ THE HUMAN SIDE OF CHEMISTRY 2: Jons Jakob Berzelius (1779-1848) 128
Concepts to Remember 131 • Key Terms Listing 132
Practice Problems By Topic 132 • Multi-Concept Problems 136
Multiple Choice Practice Test 137

Chapter 5

Atoms, Molecules, and Subatomic Particles
5.1

The Atom

140

140

■ THE HUMAN SIDE OF CHEMISTRY 3: John Dalton (1766-1844)

5.2

The Molecule

5.3

Natural and Synthetic Compounds

5.4

Chemical Formulas

5.5

143
146

147

Subatomic Particles: Protons, Neutrons, and Electrons 149
Arrangement of Subatomic Particles Within an Atom 150
Charge Neutrality of an Atom

151

Size Relationships within an Atom

Additional Subatomic Particles

152

151

141


www.pdfgrip.com

Contents
152

5.6 Atomic Number and Mass Number
Atomic Number
Mass Number

153

153

Subatomic Particle Makeup of an Atom

5.7 Isotopes

154

155

159

5.8 Atomic Masses
Relative Mass

159

161

Average Atom

Weighted Averages

162

Mass Spectrometry Experiments

165

5.9 Evidence Supporting the Existence and Arrangement of Subatomic Particles

Discharge Tube Experiments

Metal Foil Experiments

166

168

■ THE HUMAN SIDE OF CHEMISTRY 4: Ernest Rutherford (1871-1937) 169
Concepts to Remember 170 • Key Terms Listing 171
Practice Problems By Topic 171 • Multi-Concept Problems
Multiple Choice Practice Test 180

Chapter 6

Electronic Structure and Chemical Periodicity
6.1 The Periodic Law

178

182

182

6.2 The Periodic Table

183

■ THE HUMAN SIDE OF CHEMISTRY 5: Dmitri Ivanovich Mendeleev (1834-1907)

Periods and Groups of Elements

185

The Shape of the Periodic Table

187

6.3 The Energy of an Electron

188

■ THE HUMAN SIDE OF CHEMISTRY 6: Erwin Schrodinger (1887-1961)

190

190

6.4 Electron Shells

191

6.5 Electron Subshells
6.6 Electron Orbitals

Electron Spin

193

195
195

6.7 Electron Configurations
Aufbau Principle

195

Aufbau Diagram

196

Writing Electron Configurations

197

Condensed Electron Configurations

6.8 Electron Orbital Diagrams

199

201

6.9 Electron Configurations and the Periodic Law

204

6.10 Electron Configurations and the Periodic Table

6.12 Chemical Periodicity

205

211

6.11 Classification Systems for the Elements
213

Metallic and Nonmetallic Character

214

Atomic Size 215
Concepts to Remember 217 • Key Terms Listing 218
Practice Problems By Topic 218 • Multi-Concept Problems
Multiple Choice Practice Test 226

Chapter 7

185

Chemical Bonds

225

228

7.1 Types of Chemical Bonds

228

7.2 Valence Electrons and Lewis Symbols

229

■ THE HUMAN SIDE OF CHEMISTRY 7: Gilbert Newton Lewis (1875-1946)

7.3 The Octet Rule 233

7.4 The Ionic Bond Model

233

7.5 The Sign and Magnitude of Ionic Charge
Isoelectronic Species

236

238

7.6 Lewis Structures for Ionic Compounds

239

232

166

vii


www.pdfgrip.com

viii

Contents
7.7

Chemical Formulas for Ionic Compounds

7.8

Structure of Ionic Compounds

7.9

Polyatomic Ions

241

243

244

7.10 The Covalent Bond Model

246

7.11

Lewis Structures for Molecular Compounds

7.12

Single, Double, and Triple Covalent Bonds

7.13

Valence Electron Count and Number of Covalent Bonds Formed

7.14

Coordinate Covalent Bonds

7.15

Resonance Structures

7.16

Systematic Procedures for Drawing Lewis Structures

7.17

Molecular Geometry

247

250

254

263

Molecules with Two VSEPR Electron Groups

263

Molecules with Three VSEPR Electron Groups

Molecules with Four VSEPR Electron Groups
Electronegativity

255

261

Electron Pairs versus Electron Groups

7.18

264
265

268

■ THE HUMAN SIDE OF CHEMISTRY 8: Linus Carl Pauling (1901-1994)

Chapter 8

268

7.19

Bond Polarity

7.20

Molecular Polarity 273
Concepts to Remember 276 • Key Terms Listing 278

Practice Problems By Topic 278 • Multi-Concept Problems
Multiple Choice Practice Test 289

270

Chemical Nomenclature
8.1

Classification of Compounds for Nomenclature Purposes

8.2

Typesof Binary Ionic Compounds

8.3

Nomenclaturefor Binary Ionic Compounds

291

292

Fixed-Charge Binary Ionic Compounds

294

295

297

8.4

Chemical Formulas for Polyatomic Ions

8.5

Nomenclature for Ionic Compounds Containing Polyatomic Ions

8.6

301

Nomenclaturefor Binary Molecular Compounds
Common Names for Binary Molecular Compounds

8.7 Nomenclature for Acids
8.8

287

291

Variable-Charge Binary Ionic Compounds

Chapter 9

251

252

303

306

308

309

Systematic Procedures for Using Nomenclature Rules 314
Concepts to Remember 317 • Key Terms Listing 318
Practice Problems By Topic 318 • Multi-Concept Problems
Multiple Choice Practice Test 325

324

Chemical Calculations: The Mole Concept
and Chemical Formulas 327
9.1 The Law of Definite Proportions

327

■ THE HUMAN SIDE OF CHEMISTRY 9: Joseph-Louis Proust (1754-1826)

9.2

Calculation of Formula Masses

9.3

Significant Figures and Formula Mass

9.4

Mass Percent Composition of a Compound

9.5

The Mole: The Chemist's Counting Unit

328

331

333
335

337

■ THE HUMAN SIDE OF CHEMISTRY 10: Lorenzo Romano Amedeo Carlo Avogadro

(1776-1856)

9.6

339

The Mass of a Mole

341

Summary of Mass Terminology

346

9.7

Significant Figures and Avogadro's Number

9.8

Relationship Between Atomic Mass Units and Gram Units

9.9

The Mole and Chemical Formulas

348

347
347


www.pdfgrip.com

Contents
9.10

The Mole and Chemical Calculations

9.11 Purity of Samples

351

358

361

9.12

Empirical and Molecular Formulas

9.13

Determination of Empirical Formulas

362

Empirical Formulas from Direct Analysis Data

363

Empirical Formulas from Indirect Analysis Data
9.14

Chapter 10

366

Determination of Molecular Formulas 370
Concepts to Remember 375 • Key Terms Listing 375

Practice Problems By Topic 376 • Multi-Concept Problems
Multiple Choice Practice Test 385

Chemical Calculations Involving Chemical Equations
10.1

The Law of Conservation of Mass

387

387

■ THE HUMAN SIDE OF CHEMISTRY 11: Antoine-Laurent Lavoisier (1743-1794)
10.2

Writing Chemical Equations

10.3

Chemical Equation Coefficients

10.4

Balancing Procedures for Chemical Equations

10.5

Special Symbols Used in Chemical Equations

10.6

Classes of Chemical Reactions

Synthesis Reactions

388

389

390
392
397

398

398

Decomposition Reactions

399

Single-Replacement Reactions

399

Double-Replacement Reactions

400

401

Combustion Reactions
10.7

Chemical Equations and the Mole Concept

10.8

Balanced Chemical Equations and the Law of Conservation of Mass

10.9

Calculations Based on Chemical Equations—Stoichiometry

10.10

384

The Limiting Reactant Concept

403

406

407

413

10.11 Yields: Theoretical, Actual, and Percent

418

10.12 Simultaneous and Sequential Chemical Reactions 421
Combining Sequential Chemical Reaction Equations into a Single Overall Chemical

Reaction Equation 423
Concepts to Remember 425 • Key Terms Listing 425
Practice Problems By Topic 426 • Multi-Concept Problems
Multiple Choice Practice Test 436

Chapter 11

States of Matter

439

11.1

Factors that Determine Physical State

11.2

Property Differences among Physical States

11.3

The Kinetic Molecular Theory of Matter

11.4

The Solid State

11.5

The Liquid State

11.6

The Gaseous State

11.7

A Comparison of Solids, Liquids, and Gases

11.8

Endothermic and Exothermic Changes of State

11.9

Heat Energy and Specific Heat

Heat Energy Units

439

441

442

443

444

444

445
446

447

447

Specific Heat 449
11.10

Temperature Changes as a Substance is Heated

11.11 Energy and Changes of State
11.12 Heat Energy Calculations
11.13 Evaporation of Liquids

454

457

461

Rate of Evaporation and Temperature
Evaporation and Equilibrium

463

462

453

435

ix


www.pdfgrip.com

X

Contents
11.14 Vapor Pressure of Liquids

464

11.15 Boiling and Boiling Points

465

Factors that Affect Boiling Point

466

11.16 Intermolecular Forces in Liquids

Dipole-Dipole Interactions
Hydrogen Bonds

London Forces

467

468

468

471

Ion-Dipole Interactions

472

472

Ion-Ion Interactions

11.17 Hydrogen Bonding and The Properties of Water
473

Vapor Pressure

Thermal Properties

Density

473

473

475

Surface Tension 477
Concepts to Remember 477 • Key Terms Listing 478
Practice Problems By Topic 479 • Multi-Concept Problems
Multiple Choice Practice Test 486

Chapter 12

Gas Laws

485

488

12.1 Properties of Some Common Gases
12.2 Gas Law Variables

488

489

Pressure Readings and Significant Figures

493

12.3 Boyle's Law: A Pressure-Volume Relationship

494

■ THE HUMAN SIDE OF CHEMISTRY 12: Robert Boyle (1627-1691)

12.4 Charles's Law: A Temperature-Volume Relationship

494

498

■ THE HUMAN SIDE OF CHEMISTRY 13: Jacques Alexandre Cesar Charles (1746-1823)

12.5 Gay-Lussac's Law: A Temperature-Pressure Relationship

502

■ THE HUMAN SIDE OF CHEMISTRY 14: Joseph Louis Gay-Lussac (1778-1850)

12.6 The Combined Gas Law
12.7 Avogadro's Law
12.8 An Ideal Gas

504

507

511

12.9 The Ideal Gas Law

511

12.10 Modified Forms of the Ideal Gas Law Equation
The Molar Mass of a Gas
The Density of a Gas

516

516

518

Using Density to Calculate Molar Mass

519

12.11 Volumes of Gases in Chemical Reactions

520

12.12 Volumes of Gases and the Limiting Reactant Concept
12.13 Molar Volume of a Gas

Using Molar Volume to Calculate Density

527

528

12.14 Chemical Calculations Using Molar Volume
12.15 Mixtures of Gases

523

525

Standard Temperature and Standard Pressure Conditions

530

537

12.16 Dalton's Law of Partial Pressures 538
Concepts to Remember 547 • Key Terms Listing 548
Practice Problems By Topic 549 • Multi-Concept Problems
Multiple Choice Practice Test 561

Chapter 13

Solutions

564

13.1 Characteristics of Solutions
13.2 Solubility

502

564

566

Effect of Temperature on Solubility
Effect of Pressure on Solubility

566

567

Terminology for Relative Amount of Solute in a Solution

Aqueous and Nonaqueous Solutions

568

567

560

499


www.pdfgrip.com

Contents
13.3

568

Solution Formation

Factors Affecting the Rate of Solution Formation

13.4

Solubility Rules

13.5

Solution Concentrations

13.6

Percentage Concentration Unit

569

569

571
571

Using Percent Concentrations as Conversion Factors

575

13.7

Parts Per Million and Parts Per Billion Concentration Units

13.8

Molarity Concentration Unit

Using Molarity as a Conversion Factor
13.9

13.10

582

Molarity and Chemical Reactions in Aqueous Solution
Dilution Calculations

578

581

588

592

13.11 Molality Concentration Unit 596
Concepts to Remember 602 • Key Terms Listing 603
Practice Problems By Topic 603 • Multi-Concept Problems
Multiple Choice Practice Test 613

Chapter 14

Acids, Bases, and Salts
14.1

612

616

Arrhenius Acid-Base Theory

616

■ THE HUMAN SIDE OF CHEMISTRY 15: Svante August Arrhenius
(1859-1927) 617
14.2

Bronsted-Lowry Acid-Base Theory

618

Generalizations about Bronsted-Lowry Acids and Bronsted-Lowry Bases
14.3

Amphiprotic Substances

623

14.4

Mono-, Di-, and Triprotic Acids

14.5

Strengths of Acidsand Bases

14.6

Salts

14.7

Reactions of Acids

629

Reaction with Metals

629

623

625

628

Reaction with Bases

629

Reaction with Carbonates and Bicarbonates

14.8

Reactions of Bases

14.9

Reactions of Salts

631

631

631

Reaction with Metals

632

Reaction with Acids

632

Reaction with Bases

633

Reaction of Salts with Each Other
14.10

Self-Ionization of Water

633

635

Ion Product Constant for Water

636

Effect of Solutes on Water Self-Ionization

636

Effect of Temperature Change on Water Self-Ionization
Acidic, Basic, and Neutral Solutions

14.11 The pH Scale
Integral pH Values

638

639

14.12 Hydrolysis of Salts
Types of Salt Hydrolysis

640
644

645

Chemical Equations for Salt Hydrolysis Reactions
14.13 Buffers

637

638

Nonintegral pH Values

646

648

Chemical Equations for Buffer Action
14.14

620

621

Conjugate Acids and Bases

649

Acid-Base Titrations 651
Concepts to Remember 653 • Key Terms Listing 654
Practice Problems By Topic 654 • Multi-Concept Problems
Multiple Choice Practice Test 663

661

xi


www.pdfgrip.com

xii

Contents

Chapter 15

Chapter 16

Chemical Equations: Net Ionic and Oxidation-Reduction
15.1

Types of Chemical Equations

15.2

Electrolytes

15.3

Ionic and Net Ionic Equations

15.4

Oxidation-Reduction Terminology

15.5

Oxidation Numbers

15.6

Redox and Nonredox Chemical Reactions

15.7

Balancing Oxidation-Reduction Equations

15.8

Oxidation Number Method for Balancing Redox Equations

15.9

Half-Reaction Method for Balancing Redox Equations

665

666
667

671

673

678
680

681

686

15.10

Disproportionation Reactions

15.11

Stoichiometric Calculations Involving Ions 696
Concepts to Remember 699 • Key Terms Listing 700
Practice Problems By Topic 700 • Multi-Concept Problems
Multiple-Choice Practice Test 707

692

Reaction Rates and Chemical Equilibrium
16.1

Activation Energy

710

711

711

Collision Orientation

711

16.2

Endothermic and Exothermic Chemical Reactions

16.3

Factors that Influence Chemical Reaction Rates

Physical Nature of Reactants
Reactant Concentration

Presence of Catalysts

712

713

714

714

Reaction Temperature

714

715

16.4

Chemical Equilibrium

16.5

Equilibrium Mixture Stoichiometry

16.6

Equilibrium Constants

16.7

Equilibrium Position

16.8

Temperature Dependency of Equilibrium Constants

16.9

Le Chatelier's Principle

716
717

719

722

Concentration Changes

723

724
724

■ THE HUMAN SIDE OF CHEMISTRY 16: Henri-Louis Le Chatelier (1850-1936)

Temperature Changes

Pressure Changes

727

Forcing Chemical Reactions to Completion 728
Concepts to Remember 729 • Key Terms Listing 729
Practice Problems By Topic 730 • Multi-Concept Problems
Multiple Choice Practice Test 736

739

Answers to Odd-Numbered Practice Problems
Credits

Index

763

764

725

726

726

Addition of a Catalyst

Glossary

706

710

Collision Theory

Molecular Collisions

16.10

665

748

735

www.pdfgrip.com

PREFACE
Introduction to Chemical Principles is a text for students who have had little or no previous instruction in
chemistry' or whose instruction was so long ago that a thorough review is needed. The text’s purpose is to
give students the background (and confidence) needed for a subsequent successful encounter with a main
sequence, college-level, general chemistry course.
Many texts written for preparatory’ chemistry courses are simply watered-down versions of general
chemistry' texts: They' treat almost all topics found in the general chemistry' course, but at a superficial
level. Introduction to Chemical Principles does not fit this mold. My philosophy' is that it is better to treat
fewer topics extensively and have the student understand those topics in greater depth. I resisted the very’
real temptation to include lots of additional concepts in this new edition. Instead, my focus for this edition
was on rewriting selected portions to improve the clarity of presentation.
NEW FEATURES OF THE ELEVENTH EDITION

• “Chemical Insights” are used to bridge the gap between mathematics and chemistry. This

new “insight” feature, which is appended to many of the worked-out example problems in the text that
involve calculations, focuses on the element or compound that is the subject of the calculation. These
insights give information on the subject element’s/compound’s occurrence, its properties and uses, its
relationship to the environment, its relationship to living systems (biochemistry’), and so on. It is easy
for students to become so involved in the mathematics of problem solving that they completely’ forget
about the “realness” of the type of matter that is the subject of the calculation. There are 85 total insights
which address this “realness” issue.
• A “Student Learning Focus” feature is used as a mini study guide for students. These learning
objectives, found at the start of all sections of all chapters, “pinpoint” for the student what it is hoped
they will gain by study of the given section.
• New Worked-Out Example Problems. Nineteen of the 236 worked-out example problems in the
text are new. Worked-out-in-detail example problems with their extensive commentary’ constitute

one of the greatest strengths of the text.
• Extensive revision of “End-of-Chapter Problem Sets.” Although the total number of end-ofchapter problems, which already exceeds that of most other similar texts, has not increased signifi­
cantly, almost 500 of the previous edition’s 2200 problems have lx?en replaced with new problems.
A special effort was made to create new problems that address specifically the “core concepts” as­
sociated with a given chapter section’s subject matter. In most chapters several of the newly’ added
problems involve presentation of data in a “visual form” rather than in a “sentence form.” Many of the
“visual problems” involve situations where reasoning, with little or no calculation, is needed to test a
student’s grasp of a key concept.
Content changes to individual chapters. After ten successful editions of Introduction to Chemical

Principles, the need for drastic alterations in chapter ordering and chapter content does not exist. Changes
that have l)een made relate to “fine tuning" of the presentation of the subject matter. Among the most impor­
tant changes to this edition are the following:

• Chapters 4 and 5: The last four sections of chapter 4 of the previous edition (atoms, molecules,
and chemical formulas) has been moved to the start of Chapter 5. Material concerning unstable
nuclei previously' found in chapter 5 has been deleted
• Chapter 13: Material dealing with the use of the molarity' concentration unit in chemical calculations
now immediately follows the introduction of the concept of molarity’. Previously this material was
found at the end of the chapter.

xiii


www.pdfgrip.com

xiv

Preface

IMPORTANT CONTINUING FEATURES IN THE ELEVENTH EDITION
1. Development of each topic starts out at ground level. Because of the varied degrees of under­

2.

3.

4.

5.

6.

7.

8.

standing of chemical principles possessed by students taking a preparatory chemistry' course, each
topic is developed step by' step from ground level until the level of sophistication required for a
further chemistry' course is attained.
Problem-solving pedagogy is based on dimensional analysis. Over forty years of reaching
experience suggest to me that student “troubles” in general chemistry courses are almost always cen­
tered on the inability’ to set up and solve problems. Whenever possible, I use dimensional analysis in
problem solving. This method, which requires no mathematics beyond arithmetic and elementary al­
gebra, is a powerful and widely' applicable problem-solving tool. Most important, it is a method that
an average student can master with an average amount of diligence. Mastering dimensional analysis
also helps build the confidence that is so valuable for future chemistry courses.
Detailed commentary accompanies all worked-out example problems. In all chapters, one or
more worked-out example problems follow the presentation of key' concepts. These examples walk
students through the thought processes involved in solving the particular type of problem. Detailed

commentary accompanies all of the steps involved in solving a problem.
“Answer Double Check” feature. Over half (60%) of the texts worked-out examples are enhanced
by’ the feature called “answer double check.” The purpose of this feature, which is appended to the end
of the worked-out example discussion, is to encourage students to consider whether the answer they
obtain in working a problem is a reasonable answer in terms of items such as numerical magnitude,
number of significant figures present, sign convention (plus or minus), and direction of change (increase
or descrease). An unreasonable answer is often a sign that a calculator error has been made.
Significant-figure concepts are emphasized in all problem-solving situations. Routinely,
electronic calculators display’ answers that contain more digits than are needed or acceptable. In all
worked-out examples, students are reminded about these unneeded digits by the appearance of two
answers to the example: the calculator answer (which does not take into account significant figures)
and, in color, the correct answer (which is the calculator answer adjusted to the correct number of
significant figures).
Operation rules for standardizing uncertainty in numbers are used. Students often experi­
ence a relatively' high degree of frustration when they correctly solve a problem and yet obtain an
answer that differs slightly from the one given in the answer section at the back of the book. They
want to get the exact number shown in the answer section. Most often the discrepancy is due to
differing degrees of uncertainty in the input numbers used for the calculation, for example, in mo­
lecular mass values. To minimize such frustration, operational rules have been introduced for stan­
dardizing uncertainty' in input numbers. The standard mode of operation is always (1) to round all
atomic masses to hundredths before using them in molecular mass calculations, and (2) to specify'
frequently used numbers, such as Avogadro’s number, molar volume, and the ideal gas constant to
four significant figures. Using these operational rules for input numbers, student answers will match
the back-of-the-book answers to the last significant digit.
Defined terms always appear in self-standing complete sentences. All definitions are high­
lighted in the text when they are first presented, using boldface and italic type. Each defined term
appears as a complete sentence; students are never required to deduce a definition from context. In
addition, the definitions of all terms appear in a separate glossary’ found at the end of the text. All
defined terms have been reexamined to see if they could be stated with greater clarity’. The result is
a rewording of many defined terms. In addition, the number of defined terms has been increased.

There are 29 new or modified definitions in this new edition of the text.
All end-of-chapter exercises occur in matched pairs. In essence, each chapter has two inde­
pendent, but similar, problem sets. Counting subparts to problems, there are over 5000 questions
and problems available for students to use in their journey to proficient problem solving. Answers
to all of the odd-numbered problems are found at the end of the text. Thus, two problem sets exist,
one with answers and one without.


www.pdfgrip.com

Preface

9- “Multiple-Choice Practice Test” feature. The emphasis in this text has always l>een and still is

on working problems from scratch. Some, but certainly not all instructors, use this same approach
when giving class examinations. A multiple-choice question examination is another common type
of examination given. To aid students whose examinations involve multiple-choice examinations,
a 20-question "multiple-choice practice test” in included as the last feature in each chapter. It is in­
tended that students use this feature as an aid in reviewing subject matter for an upcoming multiple­
choice examination.
10. Historical vignettes are used to address some of the “people aspects” of chemistry. These
vignettes, entitled "The Human Side of Chemistry,” are brief biographies of scientists who helped de­
velop the foundations of modern chemistry. In courses such as the one for which this text is written,
it is very easy for students to completely lose any feeling for the people involved in the development
of the subject matter they are considering. If it were not for the contributions of these people, many
of whom worked under adverse conditions, chemistry would not be the central science that it is
today.
11. Marginal notes are used extensively. The two main functions of the marginal notes are (1) to
summarize key concepts and often give help for remembering concepts or distinguishing between
similar concepts, and (2) to provide additional details, links between concepts, or historical informa­

tion about the concepts under discussion.

SUPPLEMENTS
For the Instructor
Instructor Solutions Manual (download only): (ISBN: 0321815130) by Nancy J. Gardner, California

State University-Long Beach. Contains full solutions to all of the end-of-chapter problems in the text.
TestGen Computerized Test Bank: (ISBN: 0321815319) by Pamela Kerrigan, Mount Saint Vincent.

Contains approximately 1000 multiple-choice and short-answer questions, all referenced to the text.
CourseSmart: (ISBN: 0321815149) Access your college textlxxjk in online format at www.coursesmart.com .

For the Student
Student Solutions Manual: (ISBN: 0321815122) by Nancy J. Gardner, California State University-

Long Beach. Includes full solutions to all odd-numbered end-of-chapter problems and answers to all mul­
tiple choice practice test questions in the text.

xv


www.pdfgrip.com

ACKNOWLEDGMENTS
I d like to gratefully acknowledge the valuable contributions of my accuracy reviewer Andreas Lippert of
Welder State University.
Every effort has been made to rid this text of any typographical errors. I encourage my read­
ers who notice anything suspicious, or who have other questions or comments, to e-mail me at the
address below.
H. Stephen Stoker

e-mail:

Reviewers of the Eleventh Edition of Introduction to Chemical Principles, Stoker
Kiran Kuar
Joel Case
University of Wisconsin
Solano Community College
Lisa Devane
Kent Lau
Bladen Community College
San Francisco State University

Reviewers of the Tenth Edition of Introduction to Chemical Principles, Stoker
John M. Allen,
Ann van Heerden,
Indiana State University
Lonesta r College-C)Fa ir
Virginia Lea Miller,
Ashton T. Griffin,
Wayne Community College
Montgomery College
Lisa DeVane,
Douglas S. Cody,
Bladen Community College
Nassau Community College
Charles Spillner,
Andreas Lippert,
Solano Community College
Weber State University
Todd M. Johnson,

Weber State University

xvi


www.pdfgrip.com

The Science of Chemistry

1.1

Chemistry—A Scientific Discipline

1.2

Scientific Research and Technology
The Scope of Chemistry
How Chemists Discover Things—The Scientific Method
The Limitations of the Scientific Method
Application Limitations for Methods of Science

1.3
1.4
1.5
1.6

1.1 CHEMISTRY—A SCIENTIFIC DISCIPLINE
Student Learning Focus: Understand the relationship of the scientific discipline called chemistry to
other scientific disciplines and be familiar with the sub-structuring that occurs with the discipline

of chemistry.
Chemistry is part of a larger body of knowledge called science. Science is the study in
which humans attempt to organize and explain, in a systematic and logical manner,
knowledge about themselves and their surroundings.
Because of the enormous scope of science, rhe sheer amount of accumulated
knowledge, and the limitations of human mental capacity to master such a large and
diverse body of knowledge, science is divided into smaller subdivisions called scientific
disciplines. A scientific discipline fs a branch of science limited in size and scope to
make it more manageable. Examples of scientific disciplines are chemistry, astronomy,
botany, geology, physics, and zoology.
Figure 1.1 shows an organizational chart, with emphasis on chemistry, for the vari­
ous scientific disciplines. These disciplines can be grouped into physical sciences (the
study of matter and energy) and biological sciences (the study of living organisms).
Chemistry is a physical science.
Rigid boundaries between scientific disciplines do not exist. All scientific disciplines
borrow information and methods from each other. No scientific discipline is totally inde­
pendent. Environmental problems that scientists have encountered in the last two decades

1


www.pdfgrip.com

2

Chapter 1 • The Science of Chemistry’

An
organizational
chart showing the

relationship of the
scientific discipline
called chemistry
to other scientific
disciplines and also
the sub-structuring
that occurs within the
discipline of chemistry.
FIGURE 1.1

Biological Sciences
Study of Living Organisms

Physical Sciences
Study of Matter and Energy

Analytical

General

Inorganic

Organic

Physical

Noncarboncontaining
substances

Carboncontaining

substances

Energy
changes

1
1
Analysis
and
composition

Fundamental
laws
and concepts

particularly show the interdependence of the various scientific disciplines. For example,
chemists attempting to solve the problems of chemical contamination of the environment
find that they need some knowledge of geology, zoology, and botany. It is now common
to talk not only of chemists, but also of geochemists, biochemists, chemical physicists,
and so on. The middle portion of Figure 1.1 shows the overlap of the other scientific dis­
ciplines with chemistry.
Discipline overlap requires that scientists, in addition to having in-depth knowledge
of a selected discipline, also have limited knowledge of other disciplines. Discipline over­
lap also explains why a great many college students are required to study chemistry. One
or more chemistry courses are required because of their applicability to the disciplines in
which the student has more specific interest.
The body' of knowledge found within the scientific discipline of chemistry is itself
vast. No one can hope to master completely all aspects of chemical knowledge. However,
the fundamental concepts of chemistry can be learned in a relatively’ short period of time.
The vastness of chemistry’ is sufficiently large that it. like most scientific disciplines,

is partitioned into subdisciplines. The lower portion of Figure 1.1 shows the five funda­
mental branches of chemistry: analytical, general, inorganic, organic, and physical. Most
of the subject matter of this textbook falls within the realm of general chemistry, the fun­
damental laws and concepts of chemistry.
The American Chemical Society’ (ACS) is the largest scientific organization in the
world. Examination of the names of the 33 subdivisions of ACS (see Table 1.1) further


www.pdfgrip.com

Chapter 1 • The Science of Chemistry
TABLE 1.1 Names of the Divisions of the American Chemical Society
Agricultural and Food Chemistry

Fluorine Chemistry

Agrochemicals

Fuel Chemistry

Analytical Chemistry

Geochemistry

Biochemical Technology

History of Chemistry

Biological Chemistry

Industrial and Engineering Chemistry

Business Development and Management

Inorganic Chemistry

Carbohydrate Chemistry

Medicinal Chemistry

Catalysis Science and Technology

Nuclear Chemistry and Technology

Cellulose and Renewable Materials

Organic Chemistry

Chemical Education

Petroleum Chemistry

Chemical Health and Safety

Physical Chemistry

Chemical Information

Polymer Chemistry

Chemical Toxicology

Polymeric Materials: Science and Engineering

Chemistry and the Law

Professional Relations

Colloid and Surface Science

Rubber

Computers in Chemistry

Small Chemical Businesses

Environmental Chemistry

illustrates the wide diversity of subject matter and activities encompassed within the dis­
cipline of chemistry.

1.2 SCIENTIFIC RESEARCH AND TECHNOLOGY
Student Learning Focus: Understand how the fields of basic scientific research and applied sci­
entific research differ from each other and how the concepts of applied chemical research and
technology are related.

The basic activity through which new knowledge is added to rhe various scientific disci­
plines, including chemistry, is that of scientific research. Scientific research is the pro­
cess of methodical investigation into a subject in order to discover new information about
the subject. There are two general types of scientific research—basic and applied. Basic

scientific research is research whose major focus is the discovery of new fundamental
information about humans and other living organisms and the universe in which they
live. The number of scientists involved in basic scientific research is small compared to
those involved in applied scientific research. Most scientists function in the area of ap­
plied scientific research. Applied chemical research is research whose majorfocus is the
discovery ofproducts and processes that can be used to benefit humankind.
In many ways, basic scientific research is the precursor to applied scientific research.
The former is the lifeline that supplies the latter with new ideas on which to work. No
change in quality of life results from basic scientific research endeavors unless something
is done with the body of information that accumulates. Use of this information for the
betterment of humankind is the role of applied chemical research and the ensuing tech­
nology that results from it. Technology is the application of applied chemical research to
the production of new products to improve human survival, comfort, and quality of life.

3


www.pdfgrip.com

4

Chapter 1 • The Science of Chemistry’

Whether or not a given
piece of scientific knowl­
edge is technologically
used for beneficial or
detrimental purposes de­
pends on the motives of
those men and women,

whether in industry or
government, who have
the decision-making
authority. In democratic
societies, citizens (the
voters) can influence
many technological
decisions. It is important
for citizens to become
informed about scientific
and technological issues.

Technological advances began affecting our society' more than 200 years ago, and new
advances still continue, at an accelerating pace, to have a major impact on human society’.
Both benefits and detriments can be obtained from the same piece of scientific
knowledge, depending on the technology used to put it to work. For example, knowledge
concerning the closely’ related structures of the naturally-occurring substances morphine
and codeine, obtained through basic research, has led to the development of several im­
portant codeine-derivatives currently used in modern medicine as prescription painkillers
(hydrocodone and oxycodone) as well as the synthesis of the illegal drug heroin, whose
structure parallels closely that of morphine.
1.3 THE SCOPE OF CHEMISTRY
Student Learning Focus: Be able to list several areas in which chemistry applications are important
to human beings.

Although chemistry is concerned with only a part of the scientific knowledge that has
been accumulated, it is in itself an enormous and broad field. Chemistry’ touches all parts
of our lives.
Many’ of the clothes we wear are made from synthetic fibers produced by chemical
processes. Even natural fibers, such as cotton or wool, are the products of naturally’ occur­

ring chemical reactions within living systems. Our transportation usually involves vehicles
powered with energy obtained by burning chemical mixtures such as gasoline or diesel
and jet fuels. The drugs used to cure many’ of our illnesses are the result of chemical re­
search. The paper on which this textbook is printed was produced through a chemical
process, and the ink used in printing the words and illustrations is a mixture of many
chemicals. Almost all of our recreational pursuits involve objects made of materials pro­
duced by’ chemical industries. Skis, boats, basketballs, bowling balls, musical instruments,
and television sets all contain materials that do not occur naturally, but are products of
human technological expertise.
Our bodies are a complex mixture of chemicals. The principles of chemistry are
fundamental to an understanding of all processes of the living state. Chemical secretions
(hormones) produced within our bodies help determine our outward physical character­
istics such as height, weight, and appearance. Digestion of food involves a complex series
of chemical reactions. Food itself is an extremely complicated array of chemical sub­
stances. Chemical reactions govern our thought processes and how knowledge is stored
in and retrieved from our brains. In short, chemistry’ runs our lives.
A formal course in chemistry’ can be a fascinating experience because it helps us
understand ourselves and our surroundings. We cannot truly understand or even knowvery’ much about the world we live in or about our own bodies without being conversant
with the fundamental ideas of chemistry.

1.4 HOW CHEMISTS DISCOVER THINGS—THE SCIENTIFIC METHOD
Student Learning Focus: List procedural steps associated with the problem-solving approach called
the scientific method and distinguish among the terms experiment, scientific fact, scientific law,
scientific hypothesis, and scientific theory.

There is no one single correct way to do scientific research, be it basic or applied
(Sec. 1.2). Different scientists often have different approaches to solving the same
problem. However, the various approaches used always have embodied within them
a number of common characteristics that constitute the problem-solving approach
known as the scientific method.

www.pdfgrip.com

Chapter 1 • The Science of Chemistry

5

The scientific method is a set ofgeneral procedures based on experimentation and
observation used to acquire scientific knowledge and explain natural phenomena. The
procedural steps in the scientific method are as follows:
1. Identify the problem, break it into small parts, and carefully plan procedures to ob­
tain information about all aspects of this problem.
2. Collect data concerning the problem through observation and experimentation (see
Figure 1.2).
3. Analyze and organize the data in terms of general statements (generalizations) that
summarize the experimental observations.
4. Suggest probable explanations for the generalizations.
5. Experiment further to prove or disprove the proposed explanations.

Although two different
scientists rarely approach
the same problem in ex­
actly the same way, there
are always similarities in
their approaches. These
similarities are the proce­
dures associated with the
scientific method.

On occasion, a great discovery is made by accident, but the majority of scientific
discoveries are the result of the application of these five steps over long periods of
time. There are no instantaneous steps in the scientific method: applying them requires
considerable amounts of time. Even in those situations where luck is involved, it must
be remembered that chance favors the prepared mind. To take full advantage of an
accidental discovery, a person must be well trained in the procedures of the scientific
method.
The imagination, creativity, and mental attitude of a scientist using the scientific
method are always major factors in scientific success. The procedures of the scientific
method must always be enhanced with the abilities of a thinking scientist.
There are special vocabulary terms associated with the scientific method and its use.
This vocabulary includes the terms experiment, scientific fact, scientific law, scientific
hypothesis, and scientific theory. An understanding of the relationships among these terms
is the key to a real understanding of how to obtain chemical knowledge.
Experiments, Observations, and Data
The beginning step in the search for chemical knowledge is the identification of an as­
pect of a chemical system that needs study. After determining what other chemists have
already learned about the selected situation, a chemist sets up experiments for obtaining

FIGURE 1.2 Chemistry
is an experimental
science. Most
discoveries in
chemistry are made
through analysis of
data obtained from
experiments carried
out in laboratories.
(iStockphoto)

www.pdfgrip.com

6

Chapter 1 • The Science of Chemistry’

more information. An experiment is a well-defined, controlled procedure for obtaining
information about a system under study.
Performing an experiment involves making careful observations about a system
under study. An observation is a statement that describes something we see, hear, smell,
taste, or feel. Instrumentation is most often used as an aid in making observations.
Observations obtained while performing an experiment are called data. Such data may’
lx? qualitative or quantitative, with the latter being preferred. Qualitative data is nonnu merical data consisting of general observations about a system under study. The ob­
servation that ice is less dense than liquid water is an example of qualitative information
about a system. Quantitative data is numerical data obtained by various measurements
on a system under study. The information that ice has a density of 0.9170 grams per cubic
centimeter at 0°C whereas liquid water has a density’ of 0.9999 grams per cubic centimeter
at the same temperature represents quantitative data. Quantitative observations are more
useful than qualitative ones because they can be compared with each other and trends or
patterns in information can be seen.
An experiment typically involves study’ of at least two quantities, that is, variables
that have changing values. Usually, the effect of change in one variable on another vari­
able, with all other variables held constant, is measured. For example, the effect that
temperature change has on the density’ of a fixed quantity’ of a gas, with pressure held
constant, can be measured.
A well-designed experiment is always performed under controlled conditions, that
is, the values of all variables are always noted, not just those that are changing. When
such is the case, the experimental data can be reproduced, if needed, by repeating the
experiment.

EXAMPLE 1.1

Distinguishing between Qualitative
and Quantitative Data

Classify each of the following pieces of information as qualitative data or quan­
titative data.
a. The patient’s high fever has reached 105.3°F.
b. The cricket is chirping more loudly’ tonight than last night.
c. The package of candy contains about 200 gummi bears.

SOLUTION
a. Quantitative data—the temperature was measured with a thermometer.
b. Qualitative data—no measurement was made.
c. Qualitative data—even though a number is specified, it is an estimated number

rather than a measured number.

Scientific Facts

The individual pieces of new information (data) about a system under study, obtained
by carrying out experimental procedures, are called scientific facts. A scientific fact
is a reproducible piece of data about some natural phenomenon that is obtained from
experimentation. Note the word reproducible in this definition. If a given experiment is
repeated under exactly the same conditions, the same results (scientific facts) should be
obtained. To be acceptable, all scientific facts must be verifiable by anyone who has the
time, means, and knowledge needed to repeat the experiments that led to their discovery’.