An In-Depth Guide on the Meaning, Characteristics, Types, and Properties of Colloids

Before you understand the types of colloids, it is important for you to know the meaning of colloids. Colloids are a mixture of two or more substances, but are not chemically combined. Colloids are a special type of mixture of small particles of one substance dispersed through another substance. Colloids consist of gas-liquid, liquid-liquid, solid-search, or solid-gas.

Reported International Union of Pure and Applied Chemistry, colloid is a division condition in which molecules or polymolecular particles that have one dimension in parts of 1 nanometer and 1 micrometer are dispersed in various media. Substantially, each particle of each substance will be larger than an ordinary atom or molecule, but when seen with the naked eye it will be smaller.

In addition, colloids are heterogeneous mixtures that are created because one substance is dispersed (dispersed) into another substance (dispersant). Substances dissolved in colloids do not dissolve as in homogeneous mixtures but will spread to various particles in the solvent or dispersing agent. .

Properties of colloids

Once you understand what colloids are, you can conclude the characteristics of colloids. The following are the characteristics of colloids:

It looks homogeneous when seen with the naked eye, but looks heterogeneous when using an ultra microscope. Has a dispersed phase and a dispersion medium. The particle dimensions are 1-100 nm. Stable nature. Cannot be filtered, except with an ultra filtering device.

Types of colloids

yellow butter illustration (pixabay.com/rodeopix)

You need to know that colloids have many types. As is known, colloids experience a dispersed phase and a dispersion medium which produces solid, liquid and gaseous states. Reported Chemistry Libre Texts, According to the dispersing agent and dispersed substance, colloids are divided into four types, namely aerosol, sol, emulsion and foam. The following is a complete explanation.

Aerosol solids
Solid aerosol is a colloidal system with a solid dispersed phase, where gas is the dispersion medium. Examples of solid aerosols are smoke and dust.

Aerosol cair
Liquid aerosol is a colloid with liquid as the dispersed phase, and gas as the dispersing phase. Examples of liquid aerosols include mist, spray, and cloud.

Sol
Sol is a colloid with solid as the dispersed phase, while liquid is the dispersing phase. Examples are gelatin, jelly, and blood.

Solid sole
Solid sol is a colloid in which the dispersed substance and dispersing agent phases are both solid. Examples include earth, colored glass, gems and rubies.

Liquid emulsion
Liquid emulsions are colloids whose dispersed substance phase and dispersing agent phase are liquid. Examples of liquid emulsions are oil, mayonnaise, and oil in water.

Solid emulsion
Solid emulsions are colloids with the dispersed phase being liquid and the dispersing agent phase being solid. Examples are cheese and butter.

Liquid foam
Liquid foam is a colloid in which gas becomes the dispersed substance phase and liquid becomes the dispersing agent phase. Examples of liquid foam include whipped cream, soap foam, and shaving cream.

So close
Solid foam is a colloid with gas as the dispersed phase and solid as the dispersing phase. Examples include sponges, pumice stones, and marshmallows.

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Properties of colloids

illustration of alum powder (pixabay.com/id/users/azza_hafizah-5658239)

Tyndall effect
First discovered by John Tyndall. Colloids will show the Tyndall Effect, which is a condition where the light rays that appear in the colloid are caused by the interaction of light and colloid particles. The Tyndall effect causes small particles in clear substances to appear slightly blue.

Brownian motion
Brownian motion was discovered by Robert Brown because he succeeded in observing the movement of colloidal particles. He proved that colloidal particles always move and are never at rest (static) along straight paths with irregular directions.

The speed of movement will be influenced by the particle size. So, the resulting brown motion will be faster if the particle size is smaller. You can see the dust moving in the window gap that is exposed to sunlight, so you will see the dust particles moving continuously in a straight path.

Adsorption
Adsorption occurs because the colloid surface absorbs various ion particles or other compounds. For example, when you want to purify water using alum. Why is water clear because of alum? This is because pollutants in the water are absorbed by alum.

Colloid coagulation
Coagulation is the process of gathering colloidal particles and then producing a precipitate. The colloids that gather are due to the neutralization of the colloid charge which means there is no repulsive reaction.

Then, it will make the colloid particles stick together and group together to produce lumps. One example of coagulation is when you add a little acidic compound to milk, it will cause the milk to curdle and form a sediment.

How to make colloids

Condensation illustration (pexels.com/Yaroslav Shuraev)

You can make colloidal foam by dispersion and condensation. How about it, interested in making colloids? Come on, see how to make it below:

Condensation
The condensation method is the creation of colloidal particles from true solution particles. Where true solution particles or molecules and ions combine to form colloidal particles and use chemical reactions, such as redox reactions, hydraulics, and double decomposition and change of solvent.

Redox reactions are used to make sulfur sol and gold sol. Then, a hydrolysis reaction is used to make Fe (OH)3. Meanwhile, double decomposition or change of solvent is carried out to make colloidal As2s3.

Dispersed
Dispersion is a process of making colloids through suspension of large particles which then change into small particles. Dispersion is divided into three processes, namely mechanical, peptization, and arc berdia or berdig. Following is the complete explanation:

Mechanically, The process requires you to pound or grind the particles so they are small. Then, put it in a medium in the form of a hot liquid.

By peptization, the process simply involves adding the same ions to the precipitate.

In a bow or braid, The process involves flowing a high voltage current across two metal electrodes that have been dipped in a water medium.

That was an explanation of colloids. Surely you understand more about the meaning of colloids, their characteristics, properties, types and how to make them. Have a good study.

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2023-10-17 10:09:00
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