Page 6 - Theory and Problems of BEGINNING CHEMISTRY

TO THE STUDENT

This book is designed to help you understand chemistry fundamentals. Learning chemistry requires that you
master chemical terminology and be able to perform calculations with ease. Toward these ends, many of the
examples and problems are formulated to alert you to questions that sound different but are actually the same
(Problem 3.16 for example) or questions that are different but sound very similar (Problems 5.13 and 7.25, for
example). You should not attempt to memorize the solutions to the problems. (There is enough to memorize,
without that.) Instead, you must try to understand the concepts involved. Your instructor and texts usually teach
generalities (e.g., Atoms of all main group elements except noble gases have the number of outermost electrons
equal to their group number.), but the instructor asks specific questions on exams (e.g., How many outermost
electrons are there in a phosphorus atom?) You must not only know the principle, but also in what situations it
applies.
You must practice by working many problems, because in addition to the principles, you must get accustomed
to the many details involved in solving problems correctly. The key to success in chemistry is working very many
problems! To get the most from this book, use a 5 × 8 card to cover up the solutions while you are doing the
problems. Do not look at the answer first. It is easy to convince yourself that you know how to do a problem
by looking at the answer, but generating the answer yourself, as you must do on exams, is not the same. After
you have finished, compare your result with the answer given. If the method differs, it does not mean that your
method is necessarily incorrect. If your answer is the same, your method is probably correct. Otherwise, try to
understand what the difference is, and where you made a mistake, if you did so.
Some of the problems given after the text are very short and/or very easy (Problems 5.12 and 5.14, for
example). They are designed to emphasize a particular point. After you get the correct answer, ask yourself
why such a question was asked. Many other problems give analogies to everyday life, to help you understand a
chemical principle (Problems 2.13 with 2.14, 4.6, 5.15 with 5.16, 7.13 through 7.16 and 10.41, for example).
Makesureyouunderstandthechemicalmeaningofthetermspresentedthroughoutthesemester.Forexample,
“significant figures” means something very different in chemical calculations than in economic discussions.
Special terms used for the first time in this book will be italicized. Whenever you encounter such a term, use it
repeatedly until you thoroughly understand its meaning. If necessary, use the Glossary to find the meanings of
unfamiliar terms.
Always use the proper units with measurable quantities. It makes quite a bit of difference if your pet is
4 in. tall or 4 ft tall! After Chapter 2, always use the proper number of significant figures in your calculations. Do
yourself a favor and use the same symbols and abbreviations for chemical quantities that are used in the text. If
you use a different symbol, you might become confused later when that symbol is used for a different quantity.
Some of the problems are stated in parts. After you do the problem by solving the various parts, see if you
would know how to solve the same problem if only the last part were asked.
The conversion figure on page 348 shows all the conversions presented in the book. As you proceed, add
the current conversions from the figure to your solution techniques.

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