In chemistry, a<unk>  is a substance                      made by combining two or more different materials without  chemical reaction occurring. The objects do not bond together in a<unk> . A<unk>  can usually be separated back into its original components. Some examples of<unk> s are: fruit salad,ocean water and soil, some examples of heterogeneous<unk> s are salt water, iron fillings,  sulfur and salt mixed with sand.<unk> s 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 it's own chemical properties and makeup.
While there are no chemical changes in a<unk> , physical properties of a<unk> , such as its melting point, may differ from those of its components.<unk> s can usually be separated by any mechanical means.<unk> s are either homogeneous or heterogeneous.
Mixture
Isotope separation
Penetrance
Isolation 
Amplification 
Anise
Association 
Deconvolution