Air is a mixture, which is primarily made up of nitrogen and oxygen. It is more nitrogen than oxygen, with about 78 percent of the makeup being the nitrogen and 21 percent oxygen. More »

Air is not a pure substance but a mixture of different gases. It is composed of approximately 78 percent nitrogen and 21 percent oxygen, with small amounts of about a dozen other gases making up the remainder. More »

A pure substance contains only one kind of molecule, and a mixture is a combination of two or more pure substances. Distilled water, aluminum foil and table sugar are each made from only one type of particle. However, sa... More »

Air is a gaseous substance that is composed primarily of nitrogen, oxygen and argon. The air in the atmosphere that surrounds the Earth is approximately 78 percent nitrogen, 21 percent oxygen and 1 percent argon, with th... More »

Pure air is a homogeneous mixture made primarily of nitrogen and oxygen. Its elements are not readily separated or distinguished from one another. The composition of air is not uniform and may be influenced by environmen... More »

A pure metal is a substance that contains atoms of only one type of metallic element, such as aluminum, gold, copper, lead or zinc. Most metals very rarely, if ever, appear in their pure form in nature and instead must b... More »

Air is a homogeneous mixture, not a compound. The components of a mixture can be separated once they have been combined; a compound is a new substance formed by a reaction between components. More »