Mix

Concrete or concrete is a mixture of cement, water and sand in the right proportions.

A mixture is a material made up of two or more components joined, but not chemically combined. A mixture does not occur in a chemical reaction and each of its components maintains its identity and chemical properties. However, some mixtures can be reactive, meaning that their components can react with each other under certain environmental conditions, such as an air-fuel mixture in an internal combustion engine. It is the physical combination of two or more substances that retain their identities and that are mixed, forming, depending on the case, alloys, solutions, suspensions, and colloids.

They are the result of the mechanical mixing of chemical substances such as elements and compounds, without the existence of chemical bonds or other chemical changes, in such a way that each ingredient substance maintains its own chemical properties. Despite the fact that no changes are produced chemical properties of its components, the physical properties of a mixture, such as its melting point, may be different from the properties of its components. Some mixtures can be separated into their components by physical processes (mechanical or thermal), such as distillation, dissolution, magnetic separation, flotation, sieving, filtration, decantation, or centrifugation. Azeotropes are a type of liquid mixture that usually requires complicated separation processes to obtain its components.

If after mixing some substances, they react chemically, then they cannot be recovered by physical means, since new compounds have been formed.

Mixtures are classified as:

• Homogeneous.
• Heterogeneous.

The components of a mixture can be:

• Solid
• Liquid
• Gaseoso

Homogeneous mixtures

Are those mixtures of substances uniformly combined, their components cannot be differentiated even under a microscope. They are known by the name of solutions or solutions and are made up of one or more solutes and a solvent. For example, water mixed with mineral salts or with sugar or ethanol.

Heterogeneous mixtures

Heterogeneous mixture where two phases are distinguished.

A heterogeneous mixture is one that has a non-uniform composition in which its components can be easily distinguished. It is formed by two or more physically different substances, distributed unequally. The parts of a heterogeneous mixture can be easily separated. They can be thick or suspensions according to the size of the substance.

• Thick blends: the size of particles is appreciable, for example: salads, concrete (cement), etc.
• Suspensions: the particles are deposited with time, usually has the legend "accept well before use", for example: medicines, oil with water, water with heel, etc.

Colloidal dispersion

Milk is a colloid

In physical chemistry, a colloid, colloidal system, colloidal suspension or colloidal dispersion is a system made up of two or more phases, normally one fluid (liquid or gas) and the other dispersed in the form of generally very fine solid particles, with a diameter between 10^-9 and 10^-5 m.

Chemical suspension

Suspension refers to mixtures that have fine particles suspended in a liquid for a while and then settle. In the initial phase you can see that the container contains different elements. They can be separated by physical means. Some examples of suspensions are paste (water with flour) and the mixture of water with oil.

Examples of mixes

As previously indicated, mixtures can be homogeneous or heterogeneous. A homogeneous mixture is a type of mixture in which its components are not distinguished and in which the composition is uniform and each part of the solution has the same properties. A heterogeneous mixture is a type of mixture in which it is possible to observe the components, such as water and oil or lava lamps. Air is an example of a homogeneous mixture of gaseous substances: nitrogen, oxygen and minor amounts of other substances (if it does not contain suspended dust, for example filtered air). Salt, sugar, and numerous substances dissolve in water, forming homogeneous mixtures.

The table below shows the main properties of the three families of mixtures.

The following table presents examples of these three types of mixtures.