- Suspension (chemistry)
chemistry, A suspension is a heterogenousfluid containing solidparticles that are sufficiently large for sedimentation. Usually they must be larger than 1 micrometre. [ Chemistry: Matter and Its Changes, 4th Ed. by Brady, Senese, ISBN 0471215171] The internal phase (solid) is dispersed throughout the external phase (fluid) through mechanical agitation, with the use of certain excipients or suspending agents. Unlike colloids, suspensions will eventually settle. An example of a suspension would be sand in water. The suspended particles are visible under a microscope and will settle over time if left undisturbed. This distinguishes a suspension from a colloidin which the suspended particles are smaller and do not settle. [The Columbia Electronic Encyclopedia, 6th ed.] In a solution, the dissolved substance does not exist as a solid and the two are homogeneously mixed.
A suspension of liquid droplets or fine solid particles in a gas is called an aerosol. In the atmosphere these consist of fine dust and
sootparticles, sea salt, biogenicand volcanogenic sulfates, nitrates, and clouddroplets.
Suspensions are classified on the basis of the
dispersed phaseand the dispersion medium, where the former is essentially solid while the latter may either be a solid, a liquid or a gas.
Mudor muddy water, is where soil, clay, or siltparticles are suspended in water.
Floursuspended in water, as pictured to the right.
*Chalk powder suspended in water.
*Dust particles suspended in air.
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