Matter Compounds Elements Mixtures

By 1780, a number of different types of airs had been isolated and discoveries made that raised serious questions about the nature of matter. Air, earth, and water were shown to be compounds and mixtures rather than the basic elements from ancient times. 

So far, you have learned about three kinds of matter elements, compounds, and mixtures. Which box below contains only an element Which contains only a compound Which contains a mixture ... 

In this chapter we explored many of the rudiments of chemistry, including how matter is described by its physical and chemical properties and denoted by elemental and chemical formulas. We saw how compounds are different from the elements from which they are formed and how mixtures can be separated by taking advantage of differences in the physical properties of the components. Also addressed was what a chemist means by pure and how matter can be classified as element, compound, or mixture. Lastly, we saw how elements are organized in the periodic table by their physical and chemical properties. /Jong the way, you were introduced to some of the most important key terms of chemistry. With an understanding of these fundamental concepts and of the language used to describe them, you are well equipped to continue your study of nature s submicroscopic realm. 

Substance any specific kind of matter whether element, compound, or mixture. 

The word "matter" describes everything that has physical existence, i.e. has mass and takes up space. However, the make up of matter allows it to be separated into categories. The two main classes of matter are pure substance and mixture. Each of these classes can also be divided into smaller categories such as element, compound, homogeneous mixture or heterogeneous mixture based on composition. 

The chart shows a way of classifying matter. Notice that mixtures can be either heterogeneous or homogeneous and can often be separated into pure substances by physical changes. You can also see that pure matter can be elements or compounds. You ll learn more about these classes of matter in the next section. 

Even though a few elements, such as carhon and gold, are sometimes found in elemental form in nature, most of the substances we see around us consist of two or more elements that have combined chemically to form more complex substances called compounds. For example, in nature, the element hydrogen is combined with other elements, such as oxygen and carbon, in compounds such as the water and sugar used to make a soft drink. (Perhaps you are sipping one while you read.) In this chapter, you will learn to (1) deftne the terms mixture and compound more precisely, (2) distinguish between elements, compounds, and mixtures, (3) describe how elements combine to form compounds, (4) construct systematic names for some chemical compounds, and (5) describe the characteristics of certain kinds of chemical compounds. The chapter will also expand your ability to visualize the basic structures of matter. 

Chapter 2 The Classification of Matter, Elements, Compounds, and Mixtures... 

Chemists distinguish among several subcategories of matter based on composition and properties. The classifications of matter include substances, mixtures, elements, and compounds, as well as atoms and molecules, which we will consider in Chapter 2. 

Classification of matter. All matter is either a pure substance or a mixture of pure substances. Pure substances are either elements or compounds, and mixtures may be either homogeneous (uniform composition) or heterogeneous (nonuniform composition). 

Matter can be broadly classified into three types—elements, compounds, and mixtures. An element is the simplest type of matter with unique physical and chemical properties. An element consists of only one kind of atom. Therefore, it cannot be broken down into a simpler type of matter by any physical or chemical methods. An element is one kind of pure substance (or just substance), matter whose composition is fixed. Each element has a name, such as silicon, oxygen, or copper. A sample of silicon contains only silicon atoms. A key point to remember is that the macroscopic properties of a piece of silicon, such as color, density, and combustibility, are different from those of a piece of copper because silicon atoms are different from copper atoms in other words, each element is unique because the properties of its atoms are unique. 

All matter exists as either elements, compounds, or mixtures. An element consists of only one type of atom. A compound contains two or more elements in chemical combination it exhibits different properties from its component elements. The elements of a compound occur in fixed parts by mass because each unit of the compound has fixed numbers of each type of atom. Elements and compounds are referred to as substances because their compositions are fixed. A mixture consists of two or more substances mixed together, not chemically combined. The components retain their individual properties and can be present in any proportion. 

Define the characteristics of the three types of matter—element, compound, and mixture—on the macroscopic and atomic levels (S 2.1) (EPs 2.1-2.5)... 

Design a concept map that summarizes the relationships among matter, elements, mixtures, compounds, pure substances, homogeneous mixtures, and heterogeneous mixtures. 

Matter is composed of elements, compounds and mixtures. The composition of matter is summarized in Fig. 2.1. 

Let s begin our study of chemistry by examining some fundamental ways in which matter is classified. Two principal ways of classifying matter are according to physical state (gas, liquid, or solid) and according to composition (element, compound, or mixture). 

FIGURE 1.9 summarizes the classification of matter into elements, compounds, and mixtures. 

The kinds of matter we have described—elements, compounds, and mixtures—can be classified according to their composition and how they can be separated into other substances, as shown in Figure 2.6. 

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