Heterogeneous Mixtures: Characteristics, Types, Examples

The heterogeneous mixtures are those that present the naked eye in principle over a perfectly distinguishable component. It is said that they are composed of more than one material component or phase (solid, liquid or gaseous), which maintains or preserves all its properties regardless of the rest of the mixture.

These types of mixtures are very abundant here on Earth, where their elements are united by multiple natural processes or thanks to those invented by civilization. In fact, they can be observed in everyday life.

The way to know if a mixture is heterogeneous is by observing whether it has two or more material components or phases. Examples of homogeneous mixtures are a plate of rice with lentils, cereals with milk, coca cola with ice, a mixture of oil and water, orange juice with pulp, earth or sand. If you look closely, you can see that the earth and sand are made up of different components.

The material phases are the components of the heterogeneous mixture, which can be separated by applying different separation methods. These methods are generally physical, without the need to use chemical reagents, but especially mechanical work or heat.

Separation methods for heterogeneous mixtures include decantation , filtration, sieving, evaporation, dissolution, and magnetic separation.

There are heterogeneous mixtures that are homogeneous or uniform to the eye, causing confusion. However, when viewed under the microscope or at smaller scales, their distinguishable phases appear. These types of heterogeneous mixtures are known as colloids, although such a statement is often the subject of discussion.

Characteristics of heterogeneous mixtures

They are not uniform

The main characteristic of a heterogeneous mixture is its lack of uniformity, that is, that it looks the same or that its properties do not vary where it is looked at or analyzed. By having more than two distinguishable phases or components, according to the observation scale, uniformity is broken.

For example, the beach floor has sand particles, small stones, plant and animal material. Note that in this example, and in many others, the non-uniformity of the heterogeneous mixture is measured by the difference or contrast of their colors.

They have a predominant phase

Heterogeneous mixtures have a predominant phase, which is the one that is found in greater proportion than the others. This phase can be either solid, as in the case of sand grains, liquid or gaseous, and is commonly called the dispersing phase . Instead, the minority phase is called the dispersed phase .

They present more than one state of matter at the same time

Depending on the state of matter of the dispersing phase, as well as that of the dispersed phase, a group of heterogeneous mixtures is obtained whose characteristics are in complete agreement or not with the physical states of matter: solid, liquid or gaseous. For example, the beach soil is a solid smorgasbord. We will give other examples later.

Types of heterogeneous mixtures

Solid

Soil, fruit baskets, rice with lentils, and minerals from many colorful crystals are examples of solid heterogeneous mixtures. These are perhaps the simplest in terms of their method of separation, and they are also probably the most diverse.

Additional examples of solid heterogeneous mixtures will be discussed in the examples section.

Suspensions

The expression: ‘stars suspended in the sky’, helps to understand what suspensions are. This type of heterogeneous mixture consists of a predominant liquid phase, which houses or disperses small solid particles that can be appreciated with some effort.

For example, when water and sand are mixed and stirred in a glass, a suspension initially forms. However, as time passes, the same gravity ends up sedimenting the sand particles at the bottom of the glass, further demonstrating the irregular or non-uniform nature of the heterogeneous water-sand mixture.

Colloids

What if, instead of sand, much smaller particles were dispersed that managed to remain stable for longer? We would then be facing a colloid, whose predominant or dispersing phase can be solid, liquid or gas.

The dispersed particles are so small that at first glance colloids fall into the classification of homogeneous mixtures due to their apparent uniformity. However, when analyzed under the microscope or at lower scales of observation, the colloid begins to show more than one phase or component.

The water-oil mixture is the classic example of a colloid called an emulsion, as it is composed of two immiscible liquids (which do not mutually dilute). Other colloids are blood, mayonnaise, and milk.

Note that these examples have in common that they appear homogeneous at first glance, and are not considered heterogeneous mixtures until they have been analyzed further.

Methods of separation of heterogeneous mixtures

There are many separation methods to obtain one by one the components of a heterogeneous mixture. Only the most important ones will be mentioned below.

Handbook

Of all the methods, this is the simplest on a small scale. If we have a cupcake or cake with pieces of chocolate, these can be removed by the action of the same fingers or using tweezers. The same applies to rice with lentils, where the lentils would be patiently stirred with no other tools or instruments than our own hands.

Decantation

The cupcake or cake itself, including all the ingredients that formed it during its preparation, becomes a material phase recognizable at first glance. Meanwhile, the drops of chocolate, jutting on the surface, represent another solid material phase.

Jupiter crust

The gaseous crust of the planet Jupiter has more than one distinguishable phase, and even contains a huge reddish spot. This non-uniformity, together with its uneven appearance, is typical of a smorgasbord on massive scales. The deeper you go in the direction of Jupiter’s core, the more heterogeneous the picture becomes.

Mixed salad

Moving on to the culinary industry, the mixed salad is an excellent example of an everyday smorgasbord. Note that its components can be separated by manual method. Like salad, canapes or any other appetizer is classified as a smorgasbord.

Parterres (garden with plants and flowers)

The flowerbeds are another example of heterogeneous mixtures, in which the flowers become its components. Again, the more flowers there are, and the more different their colors, the more heterogeneous the flowerbed will look. This case is similar to that of the snack or any cluster of sweets.

Ham bread

The ham bread, a typical gastronomic element in the December festivities in Venezuela, is another good example of a heterogeneous mixture due to its raisins, ham, bacon and olives.

Soda

Soda and carbonated beverages are examples of heterogeneous mixtures even though they are solutions. This is due to the fact that the carbon dioxide bubbles constitute by themselves a gaseous phase or component, visibly recognizable on the surface of the liquid or within it, as in the case of the image above.

Other examples

– If sand is added to a bottle of water , the mixture would be a liquid-solid heterogeneous mixture or suspension.

– Soups or vegetable and meat broths .

– A bowl of cereal with milk is a mixed bag. 

– A pizza is heterogeneous. Added toppings such as ham or pineapple are not evenly distributed throughout the pizza, and neither is the cheese and sauce on the pizza. This means that it is a smorgasbord.

Nut mixes are heterogeneous mixes because the elements that compose it are different.

– The ocean is one of the largest heterogeneous mixtures that exist. The sea is a non-uniform distribution of animals, plants, and other essential components that make it heterogeneous.

Pollution or contamination is a heterogeneous mixture of various particles suspended in the air.

– A mud puddle is a heterogeneous mixture, since it is made up of dirt, grass, leaves, and animal waste mixed in the water.

– Although vinegar and oil are often mixed as a seasoning, the mixture itself is heterogeneous. They can stay together for a while, but they will always part after a while.

– The concrete used in construction is a heterogeneous mixture of an aggregate, cement and water .

Seasonings of salt and pepper form a heterogeneous mixture.

Sugar and sand also form a heterogeneous mixture. By mixing and looking closely, small sugar crystals and sand particles can be separately identified.

Themes of interest

Methods of separation of mixtures .

Methods of separation of homogeneous mixtures .

Mixtures: components and types .

Homogeneous mixtures .

Heterogeneous mixtures .

References

  1. Whitten, Davis, Peck & Stanley. (2008). Chemistry . (8th ed.). CENGAGE Learning.
  2. Helmenstine, Anne Marie, Ph.D. (February 11, 2020). What Is a Heterogeneous Mixture? Definition and Examples. Recovered from: thoughtco.com
  3. April Klazema. (2020). Heterogeneous Mixture Properties and Examples. Recovered from: blog.udemy.com
  4. CK-12 Foundation. (October 16, 2019). Heterogeneous Mixtures. Chemistry LibreTexts. Recovered from: chem.libretexts.org
  5. Maria Estela Raffino. (February 12, 2020). Heterogeneous mixture. Concept of. Recovered from: concept.de

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