Suspension (chimie)

Texte anglais à traduire :
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 soot particles, sea salt, biogenic and volcanogenic sulfates, nitrates, and cloud droplets.

The term is widely used in Earth sciences to describe the transport of sediments in rivers and oceans. Particles that are suspended remain suspended so long as energy (provided in the form of a current) is applied to the system. The amount of energy determines the maximum size of particle that can be suspended. In the absence of additional energy (agitation), all particles down to colloidal size will eventually settle out into a distinct phase.

It is important to distinguish suspensions from solutions which do not separate over any period of time because the intermolecular forces between the different types of molecules are of similar strength to the attraction between molecules of the same type. Entropy is then sufficient to keep a solution mixed without the need for the external input of energy which a suspension requires.