Colloid

In general, a colloid or colloidal dispersion is a two-phase system of matter; a type of mixture intermediate between homogeneous mixtures and heterogeneous mixtures.

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• In a phase colloid, small droplets or particles of one substance, the dispersed phase, are dispersed in another substance, the continuous phase.
• In a molecular colloid, macromolecules are dispersed in a continuous phase (or dispersion medium).

Many familiar substances, including butter, milk, cream, aerosols (fog, smog, smoke), asphalt, inks, paints, glues and sea foam, are colloids. This field of study was introduced in 1861 by Scottish scientist Thomas Graham.

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The size of dispersed phase particles in a colloid range from 0.001 to 1 micrometers. Dispersions where the particle size is in this range are referred to as colloidal aerosols, colloidal emulsions, colloidal foams, or colloidal suspensions or dispersions. Colloids may be colored or translucent because of the Tyndall effect. The Tyndall effect is the scattering of light by particles in the colloid.

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Colloid: Classification of colloids ►



 

Phase: Phase, from the Greek phasis, meaning 'appearance', has a number of related meanings in English....

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Butter: Butter is a dairy product made by churning fresh cream. It consists of an emulsion of water and milk proteins in a matrix of fat, with over 80% being fat. It is used as a condiment and for cooking in much the same ways as vegetable oils or lard....