A suspension of flour in water, a heterogeneous mixture

In chemistry, a mixture is when two or more different substances are mixed together but not combined chemically. The molecules of two or more different substances are mixed in the form of solutions, suspensions, and colloids. While there are no chemical changes to its constituents, the physical properties of a mixture, such as its melting point, may differ from those of the components. Some mixtures can be separated into their components by mechanical means. Azeotropes can not, at least not directly.

Mixtures are the product of a mechanical blending or mixing of chemical substances like elements and compounds, without chemical bonding or other chemical change, so that each ingredient substance retains its own chemical properties and makeup.^[1]

Mixture refers to the physical combination of two or more substances the identities of which are retained. Mixtures are either homogeneous or heterogeneous. A homogeneous mixture is a type of mixture the composition of which cannot be identified. A heterogeneous mixture is a type of mixture the composition of which can easily be identified since there are two or more phases present. Mixtures are when two or more things physically combined. When things are chemically combined together it's called a compound.

[edit] References

International Union of Pure and Applied Chemistry. "mixture". Compendium of Chemical Terminology Internet edition.