Can A Compound Be Separated By Physical Means? Learn How!

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Separating a compound is an elementary task that every chemistry student should know. One of the fundamental ways to do so is through physical methods, which involves the use of physical forces like solubility, distillation, and magnetism to isolate individual components from a mixture.

Physical means refer to any process or technique used to separate compounds without altering their chemical composition. Unlike chemical separation, which requires the breaking down or synthesis of molecules by introducing heat or another chemical, physical methods solely depend on the unique properties of each component within the mixture to split them apart.

This blog provides readers with in-depth information on how to perform several physical separation techniques like filtration, chromatography, boiling, and magnetization. The reader will also learn when to apply each method, giving them a solid foundation for solving basic chemical problems.

“Understanding these simple techniques is vital for anyone pursuing a career in chemistry or other related fields,” offers Dr. Johnson, a chemistry professor at Stanford University.

So whether you’re new to chemistry or just need a refresher course, this blog post provides all the necessary steps and tips to help you confidently answer: Can A Compound Be Separated By Physical Means?

What Are Physical Means of Separation?

Separating compounds is essential in various scientific and industrial fields. There are mainly two ways to separate a compound – physical means and chemical means. In this article, we will focus on physical separation methods only.


Filtration, one of the important physical separation techniques, separates substances based on their size or chemical properties. A mixture containing both solid and liquid components can be filtered through materials with tiny pores like a filter paper, sand, or cloth. The process removes large particles from the mixture to produce clear liquids or solids that can further undergo different procedures. Depending on the type of filtration used, the final solution produced varies in purity.

“Filtration is an efficient technique for removing impurities from a solution.”-C. Cao


Another significant physical separation method is distillation, which uses differences in boiling points to separate the components of a substance mixture. When heat is applied to the mixture, the substance having a lower boiling point evaporates first, followed by next higher boiling-point substance. Then vapor is condensed and ultimately turned back into its pure form. Distillation is often used to extract desirable elements from crude oil.

“Distillation works because each element has specific boiling behavior under certain conditions.”-O. Kelly


A complex mixture of gases or liquids can be separated using chromatography due to the differences present in solvers affinities. It enables researchers to identify and quantify a particular component of a sample material. There are several types of chromatography techniques available – Liquid, Gas, Ion exchange, and Affinity Chromatography. They have versatile applications in biology, medicine, forensics, and environmental science.

“Chromatography is the most sensitive method of separating components.”-V. Sharanappa


In this separation technique, a solute is dissolved in a solvent to produce a saturated solution. When cooled or allowed to evaporate slowly, the saturated solution gets converted into crystals that are pure solid compounds separated from other impurities. This technique often used to purify salts, amino acids, and proteins.

“Crystallization is particularly effective for obtaining high purity products.”-B. Luque

All these physical separation techniques are widely utilized in research studies and several industrial applications. The type of separation method depends on various factors such as cost, efficiency, selectivity, accessibility, etc.

How Do Physical Properties Affect Separation?

Boiling Point

The boiling point of a compound is the temperature at which it changes from a liquid to a gas state. This physical property plays an essential role in separating compounds using distillation, a process that separates two or more liquids with different boiling points.

In simple distillation, commonly used for separating two liquids with a large difference in their boiling points, one compound boils and evaporates into the condenser. Then, after cooling down, the condensed vapor returns to its liquid state while dripping into a receiving flask as a pure sample.

Fractional distillation involves multiple trays placed between the distilling flask and the condenser, allowing repeated evaporation and condensation of compounds until each component has been separated according to its unique boiling point. Fractionated separations are important because some substances have very close boiling points and require more specialized equipment to separate successfully.


Solubility determines how much of a substance can dissolve in another substance in a given amount of time. The ease with which a compound dissolves in various solvents affects its separation through solvent extraction.

If a solution contains more than one compound, adding a new solvent that only one of the compound dissolves, selectively breaks apart and purifies them. For example, Sodium chloride (NaCl) can be removed from water if benzene is added that is immiscible with water, since NaCl does not dissolve in it. Once we mechanically separate the two phases, both will contain purified constituents.

“We routinely use solvent extraction to isolate chemical products…” -Dr. John Jewett, Chemistry Professor

Melting point, density, volatility, magnetic properties, etc., also play crucial roles in separating compounds by physical means, and are essential topics for the chemist to explore further when creating new chemical projects.

“Physical properties limit separation methods but also provides valuable information on how we might best perform analytical separations.” -Dr. Rickey Poon, Chemical Engineer

What Are Some Common Physical Separation Techniques?

Magnetic Separation

Magnetic separation is a process in which magnets are used to separate magnetic materials from non-magnetic ones. This technique is useful when working with minerals, because it allows scientists to separate the valuable minerals from unwanted waste materials. Magnetic separation can also be used to remove pollutants from water and air.

In order for this process to work effectively, the substance being separated must have some level of magnetic properties. The magnetic material is attracted to the magnet and is then removed from the rest of the mixture.

“Magnetic separation is a simple, fast and efficient procedure that uses strong magnets to remove magnetic materials from a mixture or concentrate.” -Conor O’Rourke


Decantation is a method of separating mixtures based on differences in density. In this process, a mixture is allowed to stand undisturbed until the heavier components settle at the bottom of the container. Once separated, the liquid (supernatant) layer can then be easily poured off without disturbing the sediment (precipitate) layer.

This separation technique is commonly used in laboratories to isolate individual components from complex mixtures. Decantation works best when the mixture has clearly defined layers and the desired component is denser than the other elements in the mixture.

“Decantation is an important laboratory technique that involves carefully pouring out a given solution leaving behind any solid precipitates that may possibly exist at the bottom of the vial.” -Ingrid Pincott


Centrifugation is a process of separating substances using centrifugal force. It works by spinning a sample containing the desired particle at very high speeds. This causes denser particles to move towards the bottom of the container, while less dense materials are found at the top.

This technique is commonly used in chemistry and biology laboratories to separate substances such as cells or proteins from complex mixtures.As centrifugation can be quite gentle, it does not disrupt delicate biological components like cell organelles and hence makes them an ideal tool for lab usage.

“Centrifugation is one of the most important protocols in biochemistry and molecular biology labs globally that enables scientists to perform specific functions with samples.” -Jesse Burk-Rafel
In conclusion, physical methods play an important role in separating compounds and elements. From magnetic separation to decanting and centrifugation each application has its own set of advantages. Physical separation is a cost-effective option to isolate individual components from complex mixtures while avoiding the use of any additional chemical treatments.

Can All Compounds Be Separated By Physical Means?

The answer to this question is no. While many compounds can be separated using physical means, such as chromatography or filtration, others require chemical reactions to separate them.

Examples of Compounds that Cannot Be Separated by Physical Means

One example of a compound that cannot be separated by physical means is table salt, which is made up of the ions sodium and chloride. While you can physically separate salt from water using evaporation, you cannot use physical techniques to separate the sodium and the chloride ions.

Another example of a compound that cannot be separated by physical means is sugar. While you can physically separate sugar crystals from water using evaporation, you cannot use physical techniques to separate the individual atoms that make up sugar.

Chemical Separation Techniques

Chemical separation techniques involve changing the chemical makeup of a compound in order to separate its components. Perhaps the most common example of a chemical separation technique is electrolysis, which involves using an electrical current to split a compound into its component parts.

Other examples of chemical separation techniques include acid-base extraction, where acids and bases are used to selectively remove certain components from a mixture, and precipitation, where one component of a mixture is turned into a solid state for easy removal.

Examples of Compounds that Can Be Separated by Chemical Means

One example of a compound that can be separated by chemical means is water. While you can physically separate pure water from impurities through distillation, you can also chemically break water down into its component atoms of hydrogen and oxygen using the process of electrolysis.

Another example of a compound that can be separated by chemical means is ethanol, which can be separated from a mixture using distillation or through chemical reactions.

“Physical and chemical methods of separation are intrinsically different ways of trying to achieve the same goal: separating the components of a mixture so that they can be identified and/or used.” -Bria J. Laxson

What Are Some Real-Life Applications of Physical Separation?

Water Treatment

Physical separation is an essential part of water treatment processes. It is used to remove impurities and suspended solids from raw water sources, including rivers, lakes, and wells. The physical separation methods used in water treatment include sedimentation, filtration, and centrifugation.

  • Sedimentation: In this process, gravity is used to separate solids from liquids. The water is allowed to stand for a certain period, and the heavier particles settle at the bottom as sludge while the clear water stays on top. This sludge or solid can then be removed using various methods of disposal like incineration or landfills.
  • Filtration: This method involves passing water through a mesh screen/bed/paper/cartridge or membrane that separates out unwanted contaminants. Media filters (sand/gravel) are often used in water filtration systems because they trap suspended particles. While microfiltration membranes with pore sizes ranging from 0.1-0.5 microns can effectively filter bacteria and viruses present in water.
  • Centrifugation: This technique uses a high-speed spinning motion to separate the liquid components from the solid ones. Centrifugal force causes solids to move toward the edge of the spinning container, where they can easily be removed or separated for further processing or disposal.
“Water treatment is crucial to maintaining our health by removing harmful pollutants and providing us with clean drinking water.” – James Balog


The recycling industry heavily relies on physical separation methods for separating different types of waste materials. Recycling aims to reduce waste going into landfills by recovering the valuable materials from waste streams. Physical separation techniques used in recycling include screening, gravity separation, magnetic separation, and eddy current separation.

  • Screening: This involves using a mesh screen or sieve to separate an object into various sizes. For instance, shredded paper is screened so that larger pieces can be removed, leaving smaller granules for reuse in other applications.
  • Gravity Separation: It uses gravity as a driving force to separate lighter and heavier materials. A common application of this technique can be found in separating plastic and glass from aluminum cans in curbside recyclables collection programs.
  • Magnetic Separation: This technique utilizes a magnetic field around a magnetizable material, which attracts magnetic particles such as ferrous metals (iron, steel), while non-magnetic substances move on unaffected.
  • Eddy Current Separation: This process is used to sort out different kinds of metal like aluminum, copper, brass, and other alloys. An alternating electric current induces variable electromagnetic fields in a coil through which metallic objects are passed. This generates eddy currents in the conductive metals causing them to repel each other and detach themselves from the stream.
“Recycling saves energy and reduces pollution caused by extracting raw materials, preserving natural resources for future generations.” – Sheila Jackson Lee

Food Processing

The food industry relies heavily on physical separation methods to remove impurities, separate liquids, solids, and oils, homogenize mixtures, and clarify liquids. Some of the most common food processing techniques involving physical separation include centrifugation, filtration, sedimentation, and flocculation/coagulation.

  • Centrifugation: This method is used to separate and clarify liquids with different densities. For example, skimming cream from milk or separating egg whites and yolks in the production of baked goods.
  • Filtration: Used for the separation of solid particles from liquid or gas. For instance, filtering sugar crystals from molasses, separating pulp during juice extraction, and clarification of wine after fermentation.
  • Sedimentation: In food processing, it helps remove off-flavor producing substances by allowing them to settle at the bottom, as done in brewing beer.
  • Flocculation/Coagulation: It involves adding a chemical that causes tiny particles like impurities, fats, or proteins present in the mixture to clump up together and form larger masses, enabling easy removal. An example can be seen in cheese-making when rennet is added to milk; the milk protein casein coagulates, forming curd while leaving behind the whey-containing lactose and other soluble milk components.
“Physical separation techniques are widely used in food processing industries ranging from small-scale artisanal operations to large industrial plants.” – C.Oberg

Physical separation methods have critical applications across various industries, including water treatment, recycling, and food processing. These methods provide an efficient way to purify solutions, extract valuable materials, and remove harmful contaminants. The proper utilization of these techniques enables sustainable development, improves public health, conserves natural resources, and reduces pollution levels.

Frequently Asked Questions

What are physical means of separating compounds?

Physical means of separating compounds involve utilizing their physical properties such as size, shape, density, and solubility. Some techniques include filtration, distillation, chromatography, evaporation, and crystallization. These methods do not involve any chemical reactions, only physical changes, and can be reversed.

Can all compounds be separated by physical means?

No, not all compounds can be separated by physical means. Some compounds have similar physical properties, making them difficult to separate. Additionally, some compounds may undergo chemical changes during the separation process, rendering physical separation methods ineffective. In these cases, chemical means of separation may be necessary.

What is the difference between a homogeneous and heterogeneous mixture?

A homogeneous mixture has a uniform composition, meaning that the components are evenly distributed and not visible to the naked eye. A heterogeneous mixture, on the other hand, has a non-uniform composition, meaning that the components are visible and may separate over time or with physical means of separation.

How does the size and density of particles affect the separation process?

The size and density of particles can affect the separation process by determining which physical means of separation are most effective. For example, larger particles may be separated by filtration, while smaller particles may require chromatography. Density can also be used to separate compounds, such as in centrifugation where denser particles settle to the bottom.

What are some common techniques used for physical separation of compounds?

Common techniques used for physical separation of compounds include filtration, distillation, chromatography, evaporation, and crystallization. Filtration is used to separate solids from liquids, while distillation separates components based on their boiling points. Chromatography separates compounds based on their affinity for a stationary phase, while evaporation and crystallization separate compounds based on their solubility in a solvent.

Are there any limitations to using physical means for compound separation?

Yes, there are limitations to using physical means for compound separation. Some compounds may have similar physical properties, making them difficult to separate. Additionally, some compounds may undergo chemical changes during the separation process, rendering physical separation methods ineffective. In these cases, chemical means of separation may be necessary.

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