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The Collins College Outline for College Chemistry is a comprehensive guide to the fundamental concepts behind chemical reactions, bonding, equilibria, and thermodynamics, with topics ranging from simple chemical measurements and the basics of atoms and molecules to entropy, electrochemistry, and nuclear chemistry. Fully revised and updated by Dr. Steven Boone, College Chemistry includes practical "test yourself" sections with answers and complete explanations at the end of each chapter. Also included are ...
The Collins College Outline for College Chemistry is a comprehensive guide to the fundamental concepts behind chemical reactions, bonding, equilibria, and thermodynamics, with topics ranging from simple chemical measurements and the basics of atoms and molecules to entropy, electrochemistry, and nuclear chemistry. Fully revised and updated by Dr. Steven Boone, College Chemistry includes practical "test yourself" sections with answers and complete explanations at the end of each chapter. Also included are essential vocabulary definitions and sample exercises, as well as detailed images, charts, and diagrams.
The Collins College Outlines are a completely revised, in-depth series of study guides for all areas of study, including the Humanities, Social Sciences, Mathematics, Science, Language, History, and Business. Featuring the most up-to-date information, each book is written by a seasoned professor in the field and focuses on a simplified and general overview of the subject for college students and, where appropriate, Advanced Placement students. Each Collins College Outline is fully integrated with the major curriculum for its subject and is a perfect supplement for any standard textbook.
Introduction to Chemistry
Chemistry is one of the three major areas in science, along with biology and physics. In this chapter, we will first propose a definition for chemistry and discuss its scope. Then, we will turn our attention to the principal concern of chemistry: matter.
1.1 What is Chemistry?
It is important to understand the definition of chemistry in its historical context.
Chemistry—Definition, Practitioners, and History
Chemistry is the science of matter and the changes it undergoes. The main focus of chemistry is matter. All objects in the world are types of matter.
A chemist is a person who studies the composition, structure, and properties of matter and seeks to explain the changes that matter undergoes.
Modern chemistry grew out of the pseudoscience called alchemy. Alchemists searched for methods to convert base metals to gold. Robert Boyle (1627-1691) was one of the first scientists to suggest that ideas and thoughts about matter must be supported by reproducible experiments. Antoine Lavoisier (1743-1794) is credited with being the father of modern chemistry because of his pioneering experiments on the properties of matter.
Matter, Mass, and Energy
Matter is anything that has mass and occupies space. The mass of an object is a measure of the amount of matter it has. Closely related to matter is energy. Thus, chemistry also considers the relationship of matter and energy.
Energy is the capacity to do work, or more simply, the capacity tochange something.
1.2 Matter and its Properties
This section focuses on the definition of chemistry, which involves matter and the changes matter undergoes.
Composition and Structure
Composition refers to the identity and amount of the components of matter. Structure describes the physical arrangement of its particles (atoms, ions, or molecules). Some types of matter have a highly organized structure, while others are random.
Physical Properties and Changes
Chemists distinguish one type of matter from another by identifying their properties, just as people are differentiated by observing their physical appearance and personality traits. Properties are classified as being either physical or chemical. Physical properties are characteristics of a particular type of matter that can be measured without changing its composition. Density, color, melting point, boiling point, physical state, heat conductivity, and electrical conductivity are examples of physical properties of matter.
If a change occurs in the physical properties of a sample of matter without a change in composition, a physical change occurs. After such a change, the same type of matter is present but has a different set of physical properties. Changes in shape, size, and physical state are other examples of physical changes.
Chemical Properties and Changes
A chemical property describes what happens to one type of matter when it changes composition. When the matter changes its composition, a chemical reaction or chemical change occurs. Therefore, chemical properties describe the chemical reactions that matter undergoes. For example, a chemical property of gasoline is that it bums (undergoes oxidation) when ignited. Gasoline is a liquid mixture of carbon-hydrogen compounds.
Classify each of the following as a physical property, physical change, chemical property, or chemical change: (a) A blue solid, (b) an explosive liquid, and (c) a solid changes directly to a vapor without becoming a liquid.
Solution 1. 1
(a) A physical property, because it is a characteristic of a solid without reference to any other substance. (b) A chemical property, because explosive describes a chemical change that the liquid undergoes. (c) A physical change, because the solid does not change composition.
1.3 Classification of Matter
Samples of matter can be classified as being either pure substances or mixtures.
Pure substances (or, simply, substances) have a constant composition, cannot be separated into simpler components by physical methods, and undergo state changes at a constant temperature. Examples of pure substances include gold, copper, and carbon dioxide. Pure substances can be further subdivided into elements or compounds.
A mixture results when pure substances that do not react are combined. Mixtures have a variable composition, can usually be separated by physical methods, and undergo state change over range of temperatures. Mixtures can either be homogenous (those with one phase) or heterogeneous (those with two or more phases). Ocean water, concrete, air, and asphalt are four examples of mixtures.
Elements are the basic units of matter. All of the types of matter contain elements. About 115 different elements have been identified. Of these elements, 92 occur in nature, and the remaining elements are synthetic. At 25°C, 102 elements are solids, 2 are liquids, and 11 are gases.
Periodic Table of Elements
The symbols of the elements are found in the Periodic Table. This table is one of the most important tables in chemistry. Each element is located in a horizontal row called a period and in a vertical column called a group (sometimes called a family). Each period is numbered consecutively from 1 to 7. Each group of elements is assigned a Roman numeral and a letter. It has been recommended by the International Union of Pure and Applied Chemists (IUPAC) that the groups be numbered consecutively from 1 to 18. Thus, two numbering systems are now used.
Symbols of Elements
Chemists often use symbols to represent elements. The use of symbols for elements dates back to the ancient Greeks, who originally suggested that matter was composed of elements. Symbols can be one, tow, or three letters. Usually, they are the first letters of the English or Latin names. It is important to learn the symbols of the elements in the beginning of your study of chemistry.College Chemistry. Copyright © by Steven Boone. Reprinted by permission of HarperCollins Publishers, Inc. All rights reserved. Available now wherever books are sold.