Mixture
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- For other uses, see Mixture (disambiguation).
A mixture is a chemical substance which is a homogeneous or heterogeneous association without chemical bonding of chemical elements and/or chemical compounds in varying proportions and that retain their own individual properties and makeup. Mixtures can usually be separated by mechanical means.
There are no chemical changes in a mixture, i.e., each substance in a mixture keeps the same chemical properties and makeup as before. Physical properties of mixtures, e.g., the melting point, may considerably differ from those of its components.
Homogeneous mixtures are mixtures that have a definite composition and properties, i.e., any amount of a given mixture has the same composition and properties. Examples are solutions and some alloys (but not all).
Heterogeneous mixtures are mixtures without definite composition, for example, granite. Pizza is a typical humorous example of this kind of mixture. Heterogeneous mixtures are said to have several phases (not to be confused with phases of matter), i.e., parts of homogeneous composition that can be mechanically separated from the rest.
Sometimes it is difficult to draw a boundary between homogeneous and heterogeneous solutions when the sise of particles of the same phase approaches to molecular sizes. An example is colloid. The classification depends on the particular situation.
Related articles
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