Animal relationships

Social groups
The strongest competition for survival is
between members of the same species.
Solitary animals avoid each other, so
that competition is at a minimum. The
animals that live in groups must strike a
balance between the benefits of sticking
together, and the increased competition
for food and mates. Social groups range
from simple ones that provide safety in
numbers, to complex societies, where
members hunt together and protect
each other’s young.
Eusocial colony
The most highly social animals are
ants, wasps, and bees. They are eusocial,
which means there is division of labour,
with different members of the colony
performing specific jobs for the good
of the whole. The colony works for
their mother, the queen, to raise huge
numbers of yet more sisters. All work
is done by females. Only a few males
are produced every year to mate
with the next generation of queens.
When animals of two species cooperate with each other,
the relationship is known as symbiosis. There are two types.
In mutualistic relationships, both partners benefit from the
actions of the other. Commensal relationships are rarer.
They involve one animal benefiting from the association,
while the other receives no benefit, but is not harmed either.
A parasite is an organism that lives on
or inside another, known as the host.
The parasite either eats the body of the
host or consumes some of its food. The
host is disadvantaged by the relationship,
but is not killed—if it was, the parasite
would soon die as well in many cases.
A parasitoid is an animal that does kill
its host, generally as a larva eating
it alive. Once the host is dead, the
parasitoid takes on an independent
mode of life (see page 91).

What is feeding?

An organism that feeds is called a
heterotroph, a name that means
“other eater.” As the name suggests,
heterotrophs collect the nutrients
and energy they need by consuming
other organisms. Plants are called
they generate everything they need
to survive themselves. There are
several modes of feeding and every
organism specializes in getting its
food in a specific way.

Science Introduction

Science is vital to understanding everything in the Universe, from what makes
the world go around to the workings of the human body. It explains why
rainbows appear, how rockets work, and what happens when we flick a light
switch. These may seem difficult subjects to get to grips with, but science
needn’t be complex or baffling. In fact, much of science depends on simple laws
and principles. Learn these, and how they can be applied, and even the most
complicated concepts become more straightforward and understandable.
This book sets out to explain the essentials of three key sciences—biology,
chemistry, and physics. In particular, it focuses on the curricula for these
subjects taught in schools worldwide for students between the ages of 9 and 16.
This is often a crucial time for developing an understanding of science. Many
children become confused by the terminology, equations, and sheer scale of
some of the topics. Inevitably, parents—who themselves often have a limited
understanding of science—are asked to help with homework. That is where
this book can really come to the rescue.
Help Your Kids with Science is designed to make all aspects of science easy and
interesting. Beginning with a clear overview of what science is, each of the three
sections is broken down into single-spread topics covering a key area of that
science. The text is presented in short, easy-to-read chunks and is accompanied
by clear, fully annotated diagrams and helpful equations. Explanations have
been kept as simple as possible so that anyone—parent or child—can
understand them.
Another problem children often have with science is relating scientific concepts
to real life. To help them make a connection, “Real World” panels have been
introduced throughout the book. These give the reader a look at the practical
applications of the science they’ve been reading about, and the exciting ways it
can be used. Cross-references are used to link related topics and help reinforce
the idea that many branches of science share the same basic principles. A useful
reference section at the back provides quick and easy facts and explanations of
terms used in the text.
As a former research scientist, I am only too aware of how science can seem
bewildering. Even scientists can get stuck if they stray into an unfamiliar
discipline or are the first to investigate a new line of study. The trick is to get a
firm grasp on the basics, and that is exactly what this book sets out to provide.
From there you can go on to investigate how the world around you works and
explore the endless possibilities that science has to offer mankind.

The Electrical Character of Matter

If you release an object held above the floor, it falls to the floor. This is the result of
gravity, an invisible attractive force between the object and the earth. Gravity is one of
four fundamental forces that govern the operation of the universe. Another is the electromagnetic
force. Electricity and magnetism are each a part of the electromagnetic
force. All forces can be described in terms of force fields, or simply fields. A force
field is the region in space where the force is effective.
Repeated observations have shown that there are only two types of electrical charge:
positive and negative. Figure 2.20 illustrates an experiment that demonstrates the nature
of electrical charges. If a glass rod is rubbed with a silk cloth, the rod gains a positive
charge. If a pith ball, a small spongy ball made of plant fiber, is touched with a positively
charged rod, the pith ball itself becomes positively charged. When two pith balls that are
positively charged are suspended close to one another, they repel each other.
A hard rubber rod that is rubbed with fur acquires a negative charge. The ebonite
rod shown in Figure 2.20 is made from a very hard rubber used to make bowling balls.
The positively charged pith balls are attracted to the negatively charged rubber rod.
These charges are like those you develop if you scrape your feet across a rug on a
dry day. You can discharge yourself by touching another person, each of you receiving
a mild shock in the process. In each of these situations, the object acquires an electrical
charge that does not move (a static electrical charge), so the electrical force is known as
static electricity. The force is also called an electrostatic force.

Everyday Chemistry

Chemists engaged in crime analysis are
called forensic chemists. Forensic chemists
and detectives have a lot in common.
They both examine physical evidence
in the hope that they can identify some
fact, some object, or some person.
The Federal Bureau of Investigation—
the FBI—has on file the fingerprints of
approximately 79,000,000 people. If two
sets of fingerprints share 16 characteristics,
they are almost certain to come
from the same person. Matching sets
of fingerprints by hand is difficult. Computers
match fingerprint patterns more
quickly than people can match them.
In July 1999, the FBI’s Integrated Automated
Fingerprint Identification System
became fully operational, dramatically
reducing the time needed to make fingerprint
What if there were no fingerprints?
What if the suspect’s fingerprints are not
in the automated identification system?
Is there another way to reach positive
DNA because of mutations in the developing
embryos), DNA analysis can, in
theory, provide positive identification. As
a result, DNA profiling, also called “DNA
fingerprinting,” has rapidly moved into
courtrooms. Unfortunately, DNA profiling
cannot prove beyond a doubt a person’s
guilt. Fortunately for the innocent,
however, it can exonerate those falsely
A DNA sample from human tissue
is taken at a crime scene and, for comparative
purposes, from victims and
suspects. At a laboratory, the DNA is
extracted from the samples and purified.
The pure DNA is then
mixed with another substance
that, through chemical reactions,
fragments the long DNA
molecule into smaller pieces.
Technicians then treat the small
pieces so that they can be visualized,
and they sort the pieces
by size, a physical property, until
an identifying pattern forms.
The FBI has a Combined
DNA Index System program that
provides software and technical require certain categories of convicted
offenders to submit a DNA sample,
which is then placed in the database.
A feature of the Combined DNA Index
System is the National DNA Index System,
which has operated since October
1998. Over a half million DNA profiles
of convicted offenders are now in the

Commit to Improvement

By definition, you are changed as a result of learning. You need to be willing to open
your mind to new, more powerful ways of thinking about the natural world and the
process of personal intellectual development. The purpose of your college education
is to make you a better person. Are you willing to choose to commit to improving the
way you understand nature, becoming a better learner, and developing your intellect?
Let’s look as some ways to do this within the framework of this chemistry course.
Think Like a Chemist The perspective of the chemist is unique, as is the perspective
of the philosopher, the mathematician, the geographer, or the linguist. Each course
you take in college will expose you to a different way of thinking about the world.
In this chemistry course, you should work to understand the distinctive viewpoint of
a chemist. In particular, focus on the relationships among the macroscopic, directly
observable natural world, the abstract, particulate makeup of those macroscopic materials,
and the symbols that chemists use to represent both the macroscopic and particulate
world, as illustrated in Active Figure 1.7.
Embrace Multiple Ways of Knowing This chemistry course will expose you to
many ways of obtaining new knowledge. You will likely need to learn, in order of
increasing complexity, facts, rules, concepts, and problem solving. Facts are things that
you need to memorize, such as the fact that the symbol for hydrogen is H. Rules are
connections between things, and they are often expressed as mathematical relationships.
For example, the volume of a pure substance is directly proportional to its mass,
which can be expressed in symbols as V ~ m. Rules also are often expressed in the
form of if/then statements. If an element forms a monatomic anion, then the name of
the anion is the name of the element, changed to end in -ide. Concepts are mental
models of the natural world. We will present relatively simple conceptual models in
this introductory course, and as you learn more and more about chemistry in future
courses, you will find that you will need to revise and increase the complexity of your
conceptual models. Problem solving is a skill that you learn through coaching and
practice. Good problem solvers are highly regarded in all aspects of professional life.
We will help guide you in developing your problem-solving skills in this textbook, but
you will also need to put in a good deal of practice time to become a skilled problem
solver. You will likely have your favorite type of learning, and that will probably shape
your decision about your major, and ultimately, your career path, but recognize that
each mode of learning has its importance in your education. Embrace the opportunity
to become a more skilled learner in each kind of way of knowing.
Think About Your Thinking It is important not only to learn chemistry content
while in this course but also to work to develop the thinking skills that are used by
chemists. An example of a thinking skill is proportional reasoning, where you recognize
and apply relationships between two variables that are directly proportional to
one another. If you learn to see these types of relationships beyond their immediate
application, you will be able to utilize these skills in solving problems in many other
contexts. We will discuss this further in the next section.
Utilize Feedback in a Positive Manner All courses will provide you with feedback
on your performance in some way. Typically, courses have exams and/or quizzes that
assess your learning. This textbook has many end-of-chapter questions, exercises, and
problems that are accompanied by solutions at the end of the book. You can choose to
use such feedback as merely a descriptor of your learning history, such as “I earned an
80 on the gases chapter test,” or “I got that problem wrong,” or you can use the feedback
in a positive manner by thinking, “What did I do wrong, and how can I improve?”
A critical element of the process of learning is to learn from your mistakes. When
you receive a corrected exam or quiz, look at your errors and make a commitment to
change your thinking so that you don’t repeat the same error. When you solve an endof-
chapter problem incorrectly, assess what you did wrong and restudy the appropriate
material so that you can replace the misconception with a more accurate understanding
of the concept or procedure.

Commit to Utilizing All Learning Resources

College chemistry courses typically have a multitude of learning resources, which
may include lecture, this textbook and its accompanying online learning tools, laboratory,
discussion sections, help centers, tutors, instructor office hours, and your school
library. Are you ready to choose to commit to taking advantage of all of the learning
tools provided in your course? Let’s consider some of these tools in more detail.
Lecture Although it is obviously the wrong way to learn, some students choose to
skip lecture occasionally. Don’t be one of those students. Attend every lecture. If you
miss just one lecture per month in a semester course, you will probably miss 10% of
the material. That is a reduction of one letter grade worth of content in a typical course.
You need to learn the role of lecture in your course. If your instructor expects you to
listen to his or her discussion and watch presentation slides and/or material written
on the board or an overhead projector, you will need to take notes. We recommend
that your note-taking procedure follow these general steps: (1) Preview the material
by skimming the textbook. Usually, this only needs to be done every few lectures as
a new chapter is about to be introduced. Look in particular for new words and the
major concepts so that you are not caught unprepared when they are introduced in lecture.
(2) Concentrate during lecture and take notes. Don’t fool yourself; concentrating
over an extended period of time is hard work. Focus on what is being shown and said,
and work to transcribe as much material as accurately and quickly as you can. Use
a notebook that is exclusively for chemistry lecture. (3) Organize your notes as soon
as possible after lecture. Organization is the key. During a classic lecture, you often
are mostly working to transcribe the material. True learning occurs when you work
to make sense of the material and try to analyze the relationships among the concepts
that were discussed. (4) Study the textbook, work the assigned problems, and look for
connections between the lecture and the textbook. You will often find that seeing the
material presented in a slightly different way is the key to helping you make sense of a
concept. Combining your organized lecture notes with the textbook presentation of the
same topic is a powerful learning technique.
Textbook This book is a central learning resource in your chemistry course. We will
help you to become familiar with its structure in the next section.
OWL OWL, our Online Web-based Learning resource, is a homework system and
assessment and feedback tool. Using a question-creation format that varies the amount
and type of chemical substance for each online session, OWL can generate more than
100,000 chemistry questions correlated to the book. Instant feedback helps you immediately
assess your progress. (OWL is available for use only within North America.)
Student Companion Website This book’s companion Web site at http://www contains Active Figures and other materials to help you learn
in ways that a printed textbook cannot.
Laboratory If your course includes a laboratory, learn what each experiment is
designed to teach. Relate the experiment to the lecture and textbook coverage of the
same topic. Seeing something in the laboratory and getting a hands-on experience is
often just what you need to fully understand what you read in the textbook and see and
hear in the lecture.
Instructor Office Hours Many chemistry instructors are available for help outside
of class. If your instructor is not, you likely have a teaching assistant with office hours
or a tutoring center that you can visit instead. No matter the quality of instructional
resources available to you, human help is occasionally needed to accomplish your
learning goals. We recommend that you develop a list of questions and/or sample problems
that you cannot solve before you attend office hours.

The Science of Chemistry Today

Chemists study matter and its changes from one substance to another by probing the
smallest basic particles of matter to understand how these changes occur. Chemists also
investigate energy gained or released in chemical change—heat, electrical, mechanical,
and other forms of energy.
Chemistry has a unique, central position among the sciences (Fig. 1.6). It is so
central that much research in chemistry today overlaps physics, biology, geology, and
other sciences. You will frequently find both chemists and physicists, or chemists and
biologists, working on the same research problems. Scientists often refer to themselves
with compound words or phrases that include the suffix or word chemist: biochemist,
geochemist, physical chemist, medicinal chemist, and so on.
Chemistry has five subdivisions: analytical, biological, organic, inorganic, and
physical. Analytical chemistry studies what (qualitative analysis) and how much (quantitative
analysis) are in a sample of matter. Biological chemistry—biochemistry—is
concerned with living systems and is by far the most active area of chemical research
today. Organic chemistry is the study of the properties and reactions of compounds
that contain carbon. Inorganic chemistry is the study of all substances that are not
organic. Physical chemistry examines the physics of chemical change.
You will find the people who practice chemistry—chemists—in many fields. Probably
the chemists most familiar to you are those who teach and do chemical research in
colleges and universities. Many industries employ chemists for research, product development,
quality control, production supervision, sales, and other tasks. The petroleum
industry is the largest single employer of chemists, but chemists are also highly visible
in medicine, government, chemical manufacturing, the food industry, and mining.


The development of this textbook was an effort of many more people than the two
names that appear on the cover. David Shinn of the University of Hawaii at Manoa
checked for accuracy and suggested improvements. A team of reviewers analyzed the
third edition via their responses to an extensive questionnaire, and they provided wideranging
feedback that led to many of the improvements in this edition. We are sincerely
appreciative to each member of this team:
K. Kenneth Caswell, University of South Florida
Claire Cohen-Schmidt, The University of Toledo
Mapi Cuevas, Santa Fe Community College
Coretta Fernandes, Lansing Community College
Carol J. Grimes, Golden West College
Rebecca Krystyniak, St. Cloud State University
James C. Morris, The University of Vermont
Felix N. Ngassa, Grand Valley State University
Linda Stevens, Grand Valley State University
Alyssa White was our developmental editor, and she had essential input into the
vision for the fourth edition. In addition to commissioning the reviews, Alyssa is primarily
responsible for the sticky tabs and the cover design, and she made significant
contributions to the art and photography revisions. Teresa Trego was in charge of production,
and her book design is outstanding. Katherine Wilson of Lachina Publishing
Services coordinated the transition from the many separate pieces that make up a
textbook to the beautiful final product you see before you. Our copy editor, Sara Black,
continues to help us improve the quality of our writing, and we deeply appreciate her
meticulous and detailed work. We would also like to thank Lisa Weber, our Media Editor,
and Ashley Summers, Assistant Editor, for their work on the ancillary program as
well as Liz Woods, Editorial Assistant, and Nicole Hamm, our Marketing Manager.
Finally, we thank Lisa Lockwood, who coordinated the entire project from its inception
to the final product, and beyond. We are very appreciative of Lisa’s support of our
passion for understanding research on human learning and bringing it into a pragmatic
form as learning tools for chemistry students.
We are also grateful to the faculty and student users of the first, second, and third
editions of Introductory Chemistry. Their comments and suggestions over the past
twelve years have led to significant improvements in this book. We thank Melvin T.
Arnold, Adams State College; Joe Asire, Cuesta College; Caroline Ayers, East Carolina
University; Bob Blake, Texas Tech University; Juliette A. Bryson, Las Positas
College; Sharmaine Cady, East Stroudsburg State College; Bill Cleaver, University of
Vermont; Pam Coffin, University of Michigan–Flint; Jan Dekker, Reedley College;
Michelle Driessen, University of Minnesota; Jerry A. Driscoll, University of Utah; Jeffrey
Evans, University of Southern Mississippi; Donna G. Friedman, St. Louis Community
College at Florissant Valley; Galen C. George, Santa Rosa Junior College; Alton
Hassel, Baylor University; Randall W. Hicks, Michigan State University; Ling Huang,
Sacramento City College; William Hunter, Illinois State University; Jeffrey A. Hurlburt,
Metropolitan State College; C. Fredrick Jury, Collin County Community College;
Jane V. Z. Krevor, California State University, San Francisco; Joseph Ledbetter, Contra
xxviii Preface
Preface xxix
Costa College; Jerome Maas, Oakton Community College; Kenneth Miller, Milwaukee
Area Technical College; Bobette D. Nourse, Chattanooga State Technical Community
College; Brian J. Pankuch, Union County College; Erin W. Richter, University of
Northern Iowa; Jan Simek, California Polytechnic State University, San Luis Obispo;
John W. Singer, Alpena Community College; David A. Stanislawski, Chattanooga State
Tech Community College; David Tanis, Grand Valley State University; Amy Waldman,
El Camino College; Andrew Wells, Chabot College; Linda Wilson, Middle Tennessee
State University; and David L. Zellmer, California State University, Fresno.
We continue to be very much interested in your opinions, comments, critiques,
and suggestions about any feature or content in this book. Please feel free to write us
directly or through Cengage, or contact us via e-mail.
Mark S. Cracolice
Department of Chemistry and Biochemistry
The University of Montana
Missoula, MT 59812

Reference and Resource Materials

THE REFERENCE PAGES Introductory Chemistry includes two heavy-stock pages and
information on the inside book covers that we refer to as the Reference Pages. One
page is made up of tear-apart cards that may be used as shields to cover step-by-step
answers while solving examples. One side of each card has a periodic table that gives
the student ready access to all the information that table provides. The reverse side
of each card contains instructions, taken from Chapter 3, on how to use it in solving
One of the other Reference Pages includes a larger version of the Periodic Table
and an alphabetical listing of the elements. The information on the inside covers of the
book comprises a summary of nomenclature rules, selected numbers and constants,
definitions, and equations, and a mini-index of important text topics, all keyed to the
appropriate section number in the text.
APPENDIX The Appendix of Introductory Chemistry includes a section on how to use
a calculator in solving chemistry problems; a general review of arithmetic, exponential
notation, algebra, and logarithms as they are used in this book; and a section on SI units
and the metric system. Appendix III provides complete solutions to the odd- numbered
questions and many of the general questions and more challenging problems.
GLOSSARY An important feature for a preparatory chemistry course is a glossary.
With each end-of-chapter summary of Key Terms and Concepts, we remind students
to use their glossary regularly. The glossary provides definitions of many of the terms
used in the textbook, and it is a convenient reference source to use to review vocabulary
from past chapters.