In chemistry, a mixture is a set of two or more substances that come together without changing chemically. For this reason, it is possible to separate the various components of the mixtures by relatively common physical procedures, such as filtration or distillation . For example: sea water, coffee with sugar, beer, milk.
In nature there are many mixtures, with which we interact on a daily basis. One of them is the air we breathe, which is mainly made up of nitrogen and oxygen molecules, although it also contains other substances , such as carbon dioxide, water vapor, etc. Sea water is also a mixture, as we know that it contains mineral salts , organic matter in suspension and living beings , among others.
In these mixtures it is not possible to distinguish their components with the naked eye and not under microscopy, that is, the homogeneous mixtures do not present discontinuities and have uniform properties throughout. Homogeneous mixtures are known as solutions or solutions.
These mixtures do present discontinuities that give rise to the formation of different distinguishable phases, generally with the naked eye.
It is important to be clear that in mixtures there are no chemical reactions between the mixed components. Analysis of a mixture can be performed qualitatively or quantitatively:
Qualitative: It is interesting to identify what substances are present in the mixture.
Quantitative: It is interesting to know the quantity or proportion in which these are found.
Homogeneous mixtures can be liquid, gaseous or solid . The final aggregation state of the mixture is generally determined by the solvent, not the solute.
Mixtures can be separated using different methods. For example, when one dissolves table salt (a solid ) in water (a liquid ), the resulting mixture is homogeneous and liquid. In this case, if you let all the water evaporate , you would get the solid salt that was originally dissolved. If you mix sand and water, on the other hand, you will get a heterogeneous mixture. The sand will tend to form a layer at the bottom of the container, so the mixture can be easily separated using gravity separation.
Other methods of separating mixtures are decantation , crystallization , centrifugation, or thin plate chromatography. All of these procedures are very useful in research laboratories.
Examples of Mixtures:
Twenty mixtures are listed below, by way of example (including homogeneous and heterogeneous):
Baking soda in water:
It is a homogeneous mixture, with various medicinal and culinary uses.
Although at first glance it looks like something uniform, it is a heterogeneous mixture, it usually has suspended particles and its composition is highly variable. Its main component is sodium chloride (which gives it its characteristic saltiness), but it also contains other salts that are often used in cosmetics, the chemical industry, etc.
Cooking oil mix:
They are the oils that are made from more than one oleaginous species; the most common mixture is that of sunflower oil and corn. They form a homogeneous mixture.
It is a heterogeneous mixture made up of plasma, cells, hemoglobin, and many other components.
It is a heterogeneous mixture, it is achieved by combining salts of long chain fatty acids with flavoring components, colorants, glycerin, etc.
It is an extremely heterogeneous mixture, it contains mineral particles , organic matter, microorganisms , air, water, insects , roots and others.
It is a homogeneous mixture widely consumed by humans in celebrations.
In general, syrups are suspensions (a type of heterogeneous mixture), with small particles that do not dissolve completely, to which are added components such as thickeners, colorants, etc.
It is a heterogeneous mixture, the sand decants and separates forming a lower phase.
Coffee with sugar:
If it is a soluble coffee, it will have a homogeneous mixture, with the sugar dissolved in it.
Detergent in water:
Typically it is an emulsion, therefore a heterogeneous mixture.
It is a homogeneous mixture widely used for cleaning and disinfection, also as a bleach. This mixture contains active chlorine.
Alcohol for medicinal use:
It is a homogeneous mixture of ethanol in water, its concentration is normally expressed in degrees (the most common is alcohol 96 °)
Tincture of iodine:
It is used as a disinfectant. It is a homogeneous mixture.
It is a mixture of copper and tin, called an alloy, which combines the properties of these elements. It is a homogeneous mixture.
It is a homogeneous mixture of eggs, oil and some other components.
It is a mixture of limestone and clay, it has the particularity of setting or hardening in contact with water, that is why it is used in construction. It is a homogeneous mixture generally gray in color.
It is a homogeneous mixture widely used to change hair color.
It is a homogeneous mixture used to accentuate the shine and color of the shoes.
At first glance it looks like a homogeneous mixture, but it is actually a colloid , it has heterogeneous mixing properties.