Author:
Laura McKinney
Date Of Creation:
10 August 2021
Update Date:
9 May 2024
Content
In chemistry, amixture refers to the union of at least two substances, in variable proportions, without there being a combination at the chemical level. This means that each of the substances that make up the mixtures contribute their properties to the whole.
Within the mixtures, two variants can be identified, which are the following:
- Homogeneous mixtures: In this type of mixture it results very difficult to identify what the elements are that compose them. In this way, humans can only detect a single physical phase. Within the liquid homogeneous substances, called "solutions", the solvents of the solutes are identified. While solutes are in low quantity and are almost always liquid, solvents predominate in proportion. Eg wine, beer, gelatin, water and alcohol.
- Heterogeneous Mixtures: Unlike homogeneous mixtures, in these it is very easy to identify, even with the naked eye, what are the different components that make them up. This makes it much easier to separate these mixtures at the same time. Eg water and oil, water and sand.
Examples of heterogeneous mixtures
| Lettuce and tomato salad. | Water and sand. |
| Water and oil. | Helium and air. |
| Air and land. | Soup with noodles. |
| Rice and beans. | Water and sugar |
| Vinegar and oil. | Sausages with mayonnaise. |
| Water and gasoline. | Potatoes and egg. |
| Stones and wood. | Water and stones. |
| Papers and tapes. | Milk with marshmallows. |
| Water and paraffin. | Cookies with sweet and butter. |
| French fries and peanuts. | Wood and stones. |
- More in: Homogeneous and Heterogeneous Mixtures
Techniques for separating mixtures
Over time, different techniques have been developed to be able to separate the components that make up the mixtures.
Some of them are:
- Sifting: This is used for solid mixtures in the form of grains. What is then done is to pass them through one or more sieves, as necessary. In this way, while one element remains on the sieve, the rest falls.
- Magnetic separation (or magnetization): This technique is very limited since it can only be applied in those mixtures in which some of its components have magnetic properties. Then these are captured by some magnet.
- Filtration: When you want to separate those mixtures that contain insoluble solids and liquids, you can choose this option, which consists of using a funnel made of filter paper on the inside. Thus, the elements that pass through the funnel will be separated from those that are retained in it.
- Crystallization and precipitation: In this technique the temperature of the mixture is raised and thus it is concentrated, then filtered and placed in a crystallizer, where it is left to rest until the liquid evaporates. Once this happens, the solid part is preserved, in the form of crystals, on the crystallizer. As can be seen, this is the appropriate technique to separate mixtures composed of a solid solute dissolved in a solvent.
- Decantation: To separate liquids that have different densities, this technique is used, which consists of a separating funnel in which the mixture to be separated is placed. After letting it sit for a while, the densest part will be at the bottom. What is done then is to open the tap of the separating funnel, until all the substance of higher density falls, while the rest remains in said funnel.
- Distillation: Finally, this technique consists of boiling the mixture to be separated, provided that it is composed of different liquids that are soluble in each other. What happens is that different liquids require different boiling temperatures, which allows their vapors to be captured in test tubes, as they evaporate, and then return to a liquid state.
- See also: Examples of Homogeneous Mixtures
