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What is a Suspension?

A suspension is a heterogeneous mixture composed of fine solid particles not dissolving in a liquid or gaseous substance. When the mixture is not disturbed, the solid particles, which are usually larger than 1 micrometer, will settle to the bottom of the container - they are sufficiently large for sedimentation. When agitated, the internal phase (solid) is dispersed throughout the external phase (fluid).

(i). Harmatan haze - composed of tiny solid particles, such as dust particles, decaying organic matter, etc in air.

(ii). Muddy water – composed of mud particles in water.

(iii). Paints.

(iv). Sand in water

(v). Fine soot or dust in air

(vi). Droplets of oil in air

Note:

- In suspensions, the solid particles do not dissolve in the liquid or gas - this makes them different from solutions.

- The solid particles are large enough to be seen with the optical eyes, and they settle to the bottom of the container if undisturbed – this makes them different from colloids.

- Suspensions can be separated by filtration, and by a membrane.