Suspension

A suspension is a heterogeneous mixture of a solid and a liquid medium, in which the solid does not completely dissolve but is distributed in small particles in the medium. The particles range in size from 1 to 1000 microns and cannot be seen with the naked eye. Examples of suspensions are sand in water or dust in air.

An important property of suspensions is their stability. Because the particles are heavier than the liquid medium, they tend to settle to the bottom of the vessel. This process is called sedimentation. If the suspension is left undisturbed, the particles can collect in a dense layer at the bottom of the vessel. To avoid this, suspensions are often maintained with a stirrer or by shaking.

Suspensions can be separated by filtration or centrifugation. During filtration, the suspension is forced through a filter that retains the particles while the liquid medium passes through. In centrifugation, the suspension is spun in a centrifugal field, causing the particles to settle to the bottom of the tube.

Suspensions are used in many applications, such as in medicine, in the food industry and in the manufacture of paints and pigments. In medicine, suspensions can be used as medicinal products to allow slow and controlled release of active ingredients.

Overall, suspension is an important type of heterogeneous mixture used in many applications. Knowledge of the properties and possible uses of suspensions is important in order to optimize their use and avoid undesirable effects.