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In chemistry, a suspension is a heterogeneous mixture of a fluid that contains solid particles sufficiently large for sedimentation. The particles may be visible to the naked eye , usually must be larger than one micrometer , and will eventually settle , although the mixture is only classified as a suspension when and while the particles have ...
A colloid is a mixture in which one substance consisting of microscopically dispersed insoluble particles is suspended throughout another substance. Some definitions specify that the particles must be dispersed in a liquid, [1] while others extend the definition to include substances like aerosols and gels.
This mixture was once used to define 0 °C. That temperature is now defined as the triple point of Water with well-defined isotope ratios. A mixture of ammonium chloride, water, and ice form a frigorific mixture at about −17.8 °C or 0 °F. This mixture was once used to define 0 °F. [1] [2]
The pure minerals are called halite and sylvite; a physical mixture of the two is referred to as sylvinite. Because minerals are natural materials they are prone to large variations in composition. In many cases specimens are members for a solid solution family and geologists find it more helpful to discuss the composition of the family than an ...
For example, the limiting acid in liquid ammonia is the ammonium ion, NH 4 + which has a pK a value in water of 9.25. The limiting base is the amide ion, NH 2 −. NH 2 − is a stronger base than the hydroxide ion and so cannot exist in aqueous solution. The pK a value of ammonia is estimated to be approximately 34 (c.f. water, 14 [3] [4]).
In addition, a heterogeneous mixture may have a uniform (e.g. a colloid) or non-uniform (e.g. a pencil) composition. Several solid substances, such as salt and sugar, dissolve in water to form homogeneous mixtures or "solutions", in which there are both a solute (dissolved substance) and a solvent (dissolving medium) present.
For example, a solution of table salt, also known as sodium chloride (NaCl), in water would be represented as Na + (aq) + Cl − (aq). The word aqueous (which comes from aqua) means pertaining to, related to, similar to, or dissolved in, water. [1] [2] As water is an excellent solvent and is also naturally abundant, it is a ubiquitous solvent ...
The molecules in a drop of food coloring added to water will eventually disperse throughout the entire medium, where the effects of molecular diffusion are more evident. However, stirring the mixture with a spoon will create turbulent flows in the water that accelerate the process of dispersion through convection-dominated dispersion.