Compound A substance composed of two

Compound A substance composed of two or more atoms joined by chemical bonds. 

Compound A substance composed of two or more elements that have chemically reacted. The compound that results from the chemical reaction is unique in its chemical and physical properties. 

A pure substance can also be a compound, a substance composed of two or more elements in fixed definite proportions. Compounds are more common than pure elements because most elements are chemically reactive and combine with other elements to form compounds. Water, table salt, and sugar are examples of compounds they can all be decomposed into simpler substances. If you heat sugar on a pan over a flame, you decompose it into several substances including carbon... 

Compound a substance composed of two or more elements chemically combined. (1.4) A type of matter composed of atoms of two or more elements chemically combined in fixed proportions. (2.1)... 

All substances are either elements or compounds. Elements are substances that cannot be decomposed into simpler substances. On the molecular level, each element is composed of only one kind of atom FIGURE 1.5(a and b)]. Compounds are substances composed of two or more elements they contain two or more kinds of atoms [Figure 1.5(c)]. Water, for example, is a compound composed of two elements hydrogen and oxygen. Figure 1.5(d) shows a mixture of substances. Mixtures are combinations of two or more substances in which each substance retains its chemical identity. 

Compounds Most substances are compounds. A compound is a substance composed of two or more elements chemically combined. By the end of the eighteenth century, Lavoisier and others had examined many compounds and showed that all of them were composed of the elements in definite proportions by mass. Joseph Louis Proust (1754-1826), by his painstaking work, convinced the majority of chemists of the general validity of the law of definite proportions (also known as the law of constant composition) a pure compound, whatever its source, always contains definite or constant proportions of the elements by mass. For example, 1.0000 gram of sodium chloride always contains 0.3934 gram of sodium and 0.6066 gram of chlorine, chemically combined. Sodium chloride has definite proportions of sodium and chlorine that is, it has constant or definite composition. ... 

Most elements can combine with other elements to form compounds. Hydrogen gas, for example, bums in the presence of oxygen gas to form water, which has properties that are distinctly different from those of either l drogen or oxygem Thus, water is a compound, a substance composed of atoms of two or more elements chemically united in fixed proportions [Figure 1.6(c)]. The elements that make up a compound are called the compound s constituent elements. For example, the constituent elements of water are hydrogen and oxygen. 

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