Heterogeneous Mixture: Important Properties, Types, Examples, Separation Process

A heterogeneous mixture is one that is not uniform and contains visible, separate things or particles. Two or more constituent elements mix but remain physically distinct in heterogeneous mixes. The chemical characteristics of the components do not change, and the individual components may be seen with the naked eye. ‘Hetero’ in a prefix implies different. 

Heterogeneous Mixtures
Heterogeneous Mixtures

What is Heterogeneous Mixture?

A mixture is made up of two or more pure substances that have not been chemically mixed and maintain their inherent chemical characteristics. The mixture with a non-uniform composition is referred to as a heterogeneous mixture.

Heterogeneous mixtures do not blend smoothly and do not have a homogenous composition. The composition varies with at least two phases that stay distinct from one another and have clearly defined features. Individual components are frequently detectable and may be separated using either chemical or physical techniques as a result of these features.

Properties of Heterogeneous Mixture

  • Heterogeneous mixes are made up of at least two separate components, ingredients, or phases (any part of a sample that has uniform composition and properties).
  • Mixtures may typically be separated.
  • Phases combine but preserve their chemical identities.
  • Mixtures of multiple states of matter (gas, liquid, solid) are inherently heterogeneous.

Types of Heterogeneous Mixture

There are two main types of heterogeneous mixtures:

  • Colloid
  • Suspension

Colloids

Colloids are mixtures of tiny, insoluble particles floating in another material.

Colloids can be given multiple names depending on their condition and the material in which they are suspended:

Sol: Solid particles suspended in a liquid
Example: Paints include pigment particles suspended in water.
Emulsion: Liquid particles suspended in a liquid.
Example: Oil in water
Foam: Gas particles suspended in a liquid or solid.
Example: soap bubbles.
Aerosols are liquid/solid particles suspended in a gas.
Example: smoke: soot in carbon dioxide.

Suspension

Suspensions are a type of combination in which big, insoluble particles are suspended in another substance but eventually settle.

Flour in water is an example of a suspension. The flour particles are suspended in the water when it is first swirled. But, after a while, the flour will settle to the bottom.

Although colloids and suspensions are similar to solutions, they are not the same. There are two major distinctions. The first difference is that colloids/suspensions have two phases because the particles are insoluble, whereas solutions have just one phase because the particles are soluble.

Examples of Heterogeneous Mixtures

Heterogeneous Solid Mixtures

Solid heterogeneous mixtures can comprise liquid or gaseous components, yet they behave as solids as a whole.

Mixed nuts –  They are a form of heterogeneous mixture that may be split into different components. 
Rocks in the sand – The rocks in the sand at the beach are a mixed bag. Natural processes have mingled sand, stones, shells, and even live organisms, dispersing them throughout the shore.
Salad is an example of a diverse food that includes lettuce, cheese, seeds, tomatoes, broccoli, and other veggies.

Soil – A heterogeneous mixtures example is soil. It mixes various dissimilar components, including as stone, clay, rotting plant material, and even live creatures.

Heterogeneous Liquid Mixtures

A liquid heterogeneous combination is one that has numerous separate components yet behaves like a liquid as a whole. Here are a couple of such examples:

Ice cubes in a drink – When you first place ice cubes in a glass of water or tea, the combination is heterogeneous. There are two unique components: ice and tea or water.
Oil and water – When oil and water are together, they do not mix. Since they are two independent pieces, they are a heterogeneous combination.
Mud puddle – Mud puddles are a complex combination. Dirt, leaves, and other runoff combine with rainfall and pool to form a combination in which the component elements may be easily seen or separated.

Heterogeneous Gaseous Mixtures

Certain heterogeneous mixes consist mostly of gaseous components. Gaseous mixtures can contain liquids or even solids, yet they always behave like gases.

Mist and fog are heterogeneous mixes because small droplets of water linger clearly in the air. 
Smog is a heterogeneous collection of suspended particles and contaminants in the air. Smog is a hazardous heterogeneous mixture because the unclean particles that make up the smog can be taken from the air and inhaled into the lungs.
Smoke from a fire is a heterogeneous mixture that combines chemicals from the fire’s fuel and CO2 from the oxidation process with the air surrounding the flame.

Clouds: Water vapor rises into the atmosphere and combines with air to form visible clouds.

Multi-Phase Mixtures

While practically all heterogeneous mixes contain certain components in various phases, many are distinguished by the presence of unique, distinct phases of matter.

A bowl of cereal is an illustration of a multi-phase combination. Here you have a good mix of solid cereal with liquid milk.
A chocolate chip cookie is a heterogeneous composition. Each mouthful may have a variable quantity of chocolate chips.

Carbonated water (or carbonated anything) is a multi-phase heterogeneous combination of gaseous carbon dioxide (CO2) bubbling over liquid water (H2O).

Lava – Volcanic lava is a multi-phase combination of solid pieces of rock surrounded by hot, molten stone. It may be too hot to touch, yet it has distinct pieces.
Sand and water – If you put sand and water in a glass and let them settle, you will see that the sand is at the bottom and the water is on top. This is because they do not combine.

Separation of Heterogeneous Mixtures

A heterogeneous mixture can be separated in a variety of methods as homogeneous mixtures. The most apparent method is to manually separate different components. For example, we may manually separate specific components of trail mix (such as raisins, dried fruits, almonds, and so on). If certain components are magnetic, they may be separated using electromagnets, a process known as magnetic separation. Separating components can also be accomplished by centrifugation. Separating individual components can also be accomplished by filtering the mixture via various filter layers (or sieves). Another method is the flotation procedure.

Handpicking: We can hand pick the larger particles seen by our naked eyes. For example: separating sand from grains.

Threshing: This procedure is primarily used during agricultural harvesting. As wheat stalks are harvested, they are often dried. By pounding the dry stalks to shake off the dried grains, the grain is separated from the stalks and crushed into the floor.

Winnowing: As the grains are gathered from the process of threshing, it needs to be cleansed away of husks and chaffs before it is made into flour. Typically, the separation of the mixture is accomplished with the assistance of wind or blowing air. When farmers drop the combination from a given height to the ground, the husk and chaff are blown away by the powerful wind. The heavier grains are gathered in one location.

Evaporation: It is a process for separating a combination, most typically a solvent-and-soluble-solid solution. In this procedure, the solution is heated until the organic solvent evaporates, converting into a gas and primarily leaving behind the solid residue.
The procedure separates the liquid and solid components. The technique usually requires heating the mixture until no liquid remains. Before applying this procedure, the combination should only comprise one liquid component, unless it is not required to separate the liquid components. This is because all liquid components will evaporate over time. Evaporation is a good way to separate a soluble material from a liquid.

Sieving: A sieve is a shallow vessel with tiny holes at the bottom. An iron mesh can also be used as a sieve in specific instances. The process of dividing a mixture with a sieve is known as sieving. Sieving is a technique used to separate solid mixes containing components of varied sizes.

The combination, which comprises varied sizes of components, is put in a sieve, which is continually pushed back and forth. The bigger particles of the mixture are unable to pass through the sieve’s microscopic pores and hence remain stuck.

Sedimentation/Filtration: It is the most frequent method of separating a liquid from an insoluble material. Imagine the following scenario: a sand-water combination. Filtration removes solid particles from the liquid in this situation. Filtering agents such as filtering paper and other materials are frequently utilized.

Distillation: It is an efficient method for separating combinations of two or more pure liquids. Distillation is a purification procedure that includes vaporizing and then condensing and separating the elements of a liquid combination.

In simple distillation, a mixture is heated until the most volatile component vaporizes at the lowest temperature. After traveling through a chilly tube, the vapor condenses back into liquid (a condenser). Distillate is the collected condensate.

Magnetic Separation
Magnetization is a technique used to attract magnetic materials. Magnetic separation is the separation of two solid mixtures, one of which possesses magnetic characteristics. It is based on the separation of magnetic and non-magnetic materials. Iron particles in an iron-sulphur combination are drawn to the magnet and separated from the non-magnetic material.

References

  • Whitten K.W.; Gailey K. D.; Davis R. E. (1992). General Chemistry (4th ed.). Philadelphia: Saunders College Publishing. ISBN 978-0-03-072373-5.
  • https://byjus.com/chemistry/heterogeneous-mixture-homogeneous-mixture/
  • https://www.geeksforgeeks.org /separation-of-mixtures/
  • https://www.thoughtco.com/definition-of-heterogeneous-mixture-and-examples-605206
  • IUPAC (1997). “Mixture.” Compendium of Chemical Terminology (the “Gold Book”) (2nd ed.). Oxford: Blackwell Scientific Publicationsdoi:10.1351/goldbook
  • https://www.studysmarter.co.uk/explanations/chemistry/physical-chemistry/types-of-mixtures/
  • https://education.seattlepi.com/examples-heterogeneous-mixture-pure-substance-4841.html
  • McClements, David J. (2008). “Lipid-Based Emulsions and Emulsifiers“. In Akoh, Casimir C.; Min, David B. (eds.). Food Lipids: Chemistry, Nutrition, and Biotechnology. Food Science and Technology (3rd ed.). Boca Raton, Florida: CRC. ISBN 978-1420046649.

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Jyoti Bashyal

Jyoti Bashyal is an enthusiastic researcher currently working in the field of computational chemistry. She is a graduate student from the Central Department of Chemistry, Tribhuvan University. As a writer, she relishes creative writing and believes in hard work with a positive mindset.

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