mixture

chemistry and physics

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July 23, 2026

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In chemistry, a mixture is a substance comprising two or more components that are not chemically bonded. These components retain their individual identities and can often be separated by physical means. Mixtures can be classified as either homogeneous or heterogeneous.12

A homogeneous mixture, also known as a solution, has a uniform composition throughout. The components are evenly distributed, and it's impossible to see the individual parts. Examples include saltwater and air.2

A heterogeneous mixture has a composition that varies from one part to another. The different components are visibly distinct. Examples include a salad or a pile of sand and rocks. Liquids, like water, can be pure or form mixtures, such as seawater, where various substances are dissolved.34

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chemical element
General observations
…naturally occurring matter are physical mixtures of compounds. Seawater, for example, is a mixture of water and a large number of other compounds, the most common of which is sodium chloride, or table salt. Mixtures differ from compounds in that they can be separated into their component parts by physical…
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…naturally occurring matter are physical mixtures of compounds. Seawater, for example, is a mixture of water and a large number of other compounds, the most common of which is sodium chloride, or table salt. Mixtures differ from compounds in that they can be separated into their component parts by physical…
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separation and purification
Basic concepts of separations
…amounts of substances in a mixture. In chemical methods, one may start with a completely homogeneous mixture (a solution) or a heterogeneous sample (e.g., solid plus liquid). In the act of separation, some particles are either partially or totally removed from the sample.
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…amounts of substances in a mixture. In chemical methods, one may start with a completely homogeneous mixture (a solution) or a heterogeneous sample (e.g., solid plus liquid). In the act of separation, some particles are either partially or totally removed from the sample.
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gas
Viscosity
…pertains to the viscosity of mixtures. A viscous syrup, for example, can be made less so by the addition of a liquid with a lower viscosity, such as water. By analogy, one would expect that a mixture of carbon dioxide, which is fairly viscous, with a gas like hydrogen, which…
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…pertains to the viscosity of mixtures. A viscous syrup, for example, can be made less so by the addition of a liquid with a lower viscosity, such as water. By analogy, one would expect that a mixture of carbon dioxide, which is fairly viscous, with a gas like hydrogen, which…
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gas
Viscosity
…of the viscosity of a mixture can also be explained by the foregoing calculation. In a mixture of a light gas and a viscous heavy gas, both types of molecules have the same average energy; however, most of the momentum is carried by the heavy molecules, which are therefore the…
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…of the viscosity of a mixture can also be explained by the foregoing calculation. In a mixture of a light gas and a viscous heavy gas, both types of molecules have the same average energy; however, most of the momentum is carried by the heavy molecules, which are therefore the…
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