Introduction to Chemical Principles

9780131850064

0131850067

Introduction to Chemical Principlesis a text for students who have had little or no previous instruction in chemistry or who had such instruction long enough 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 f9r this edition was on rewriting selected portions to improve the clarity of presentation. Important Features of the Eighth Edition Development of each topic starts out at "ground level."Because of the varied degrees of understanding 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.Thirty-five years of teaching experience suggest to me that student "troubles" in general chemistry courses are almost always centered 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 algebra, 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. In addition, an unworked practice exercise is coupled to each worked-out example. It is intended that students work this exercise immediately after examining the worked-out example. A section at the end of each chapter gives the answers to these unworked practice exercises. In total, the number of worked-out examples is significantly greater than that found in most texts and has increased from that in the previous edition of this work. 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 experience 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 molecular mass values. To minimize such frustration, operational rules have been introduced f