Mixture Characteristics

A mix is the combination of two or more pure substances, which can be solid, liquid or gaseous, and which do not enter into a chemical reaction or are transformed. The particles of these substances are dispersed among themselves, which gives the mixture certain physical properties. The mixture then acts like a new, different material.

Although it is generally considered that the components retain their chemical nature, their alteration is possible when conditions such as extreme heat or high pressure. On the other hand, for there to be mixtures such as emulsions (such as mayonnaise, which contains water and oil), chemical substances called surfactants, and a lot of agitation.

Mixtures are found in nature, forming the water of the seas, the air we breathe, minerals and many substances present in the organisms of living beings. In addition, industrial processes are responsible for creating and manipulating them to reach the final products, which will satisfy the needs of consumers.

Mix types

In a mixture, the particles of the components, depending on how dispersed they are among each other, will create the so-called phases, what are the parts of the mixture that can be distinguished by their color or by their separation. That said, mixtures can be classified into:

• Homogeneous mixtures.
• Heterogeneous mixtures.

The Homogeneous mixtures are those that only present A phase. For example, water in which a little salt has been dissolved has a crystalline whitish color, which is uniform. You cannot see the salt particles flitting through the liquid. In this type of mixtures are cataloged:

• All dilute and saturated solutions, calls too true solutions, in which the components, which can be solid or liquid in a liquid medium, are not distinguished by simple sight and can only be separated by physical methods such as filtration, decantation, distillation.
• Colloids: They are supersaturated aqueous solutions, which carry particles of a solid with diameters ranging between 1 nm and 1 μm, so small that they cannot be separated by filtering.
• Alloys: They are homogeneous mixtures formed by metals. Examples of alloys are steel, made of iron and carbon, the bronze, made of copper and tin, and the brass.

The heterogeneous mixtures are those in which they are appreciated two or more phases. For example, a stone that contains various minerals, such as zinc (ZnS), iron (FeS), and cadmium (CdS) sulphides, shows the metallic sparkles of each. In this type of mixes, the following are cataloged:

• Simple or rude mixes, which are combinations of granulated solids, the particles of which can be seen with the naked eye. This is the case of beach sand, which contains crystals of many minerals such as calcium carbonate (CaCO₃) and silicon dioxide (SiO₂).
• Suspensions, which are mixtures that carry the particles of a solid held in the liquid medium of the solvent. If this mixture is left to stand for a while, the particles will settle. It is easy to separate the components by decantation or filtration. For this mixture to have uniform properties, it must be shaken; thus, the particles will be completely dispersed.

Mixture characteristics

All mixtures are distinguished by a number of characteristics:

• They have two or more components
• Variable proportions of its components
• Its components retain their properties
• Its components can be separated by physical methods
• Arrangement of its component particles
• They act as a different material to its components

They have two or more components

Mixtures are made up of the combination of two or more substances. These can be pure, such as elements or chemical compounds, or mixtures in turn.

For example:

• A stone that contains various minerals is a solid mixture of several pure substances, such as calcium carbonate (CaCO₃) and magnesium carbonate (MgCO₃).
• Air is a mixture of several gases: 78% nitrogen, 21% oxygen, and 1% other gases.

Variable proportions of its components

The components of a mixture can be found in various proportions, which will give it different properties each time.

For example:

• A steel to which little carbon has been added, less than 1%, will take a bit of hardness. If this proportion is raised, adding 5% of carbon to the cast iron, you will have a reinforced carbon steel.
• If to a liquefied petroleum gas or LP gas, which contains 70% propane (C₃H₈) and 30% butane (C₄H₁₀), a little more butane is added, this mixture will take on more calorific power.

Its components retain their properties

The components of a mixture continue to have their physical and chemical properties and are not transformed, so that they are easy to separate from the combination.

For example:

• In a mixture containing sand and marble dust, the components will continue to act as if they were alone. In this case, they can be separated by means of a sieve, with a mesh number that can separate the sand granules from those of the marble.

Its components can be separated by physical methods

The substances that make up a mixture can be separated by methods suitable for their physical state. The separation will be much easier if the mixture is heterogeneous.

For example:

• If the mixture is a liquid containing a dissolved solid, these components can be subjected to filtration, evaporation or decantation.
• If the mixture consists of granules of one solid with the granules of another, a sieve or sieve can be used to separate them. The finer granules will pass through the sieve mesh and the larger ones will stay on top of it.

Arrangement of its component particles

In the Homogeneous mixtures, the particles are evenly dispersed, so each part of the mixture is identical to the other, and will have the same physical properties. In the heterogeneous mixtures, the particles of each component are arranged irregularly, so that the concentration will be different in each part.

In suspensions that have been allowed to stand for a while, the particles have settled to the bottom of the container, thus the concentration of the solid component will be higher in this part than on the surface, where you can have a very liquid diluted.

They act as a different material to its components

There are man-made mixtures that have different properties than the original separate materials. This is the case of alloys, for example:

• Iron metal, by itself, is brittle under high stress. When combined in cast iron with a percentage of carbon, you will have a carbon steel, which is so resistant that it can be used to build structures for buildings.
• Conventional steel can rust and, if this process continues, the material deteriorates to such a degree that it can break. This steel is treated in the foundry with suitable materials, so that there is a stainless steel, a very useful material for industrial processes that handle aggressive substances.

Follow with:

• Homogeneous mixtures.
• Heterogeneous mixtures.