What Is A Colloid?
A colloid is a mixture with particles ranging between 1 and 1000 nanometers in diameter and still able to remain evenly distributed throughout the solution. In colloids the substances remain dispersed and do not settle to the bottom of the container.
The colloid particles are generally larger than those in a solution and smaller than those in a suspension. The particles of the colloidal solutions do not diffuse or pass through parchment paper but they easily diffuse or pass through filter paper.
A colloidal system may consist of one kind of colloid or a combination of solid, liquid or gas colloids dispersed in the medium. A system of liquid or solid particles colloidally dispersed in a gas is referred to as an aerosol. A system of solid substances or water-insoluble liquids colloidally dispersed in liquid water is referred to as hydrosol.
Colloids may be translucent due to the Tyndall effect where light is scattered by particles in the mixture. Other colloids may be opaque or have a slight color.
Examples of Colloids
Aerosols
- Fog
- Insecticide
- Clouds
- Smoke
- Dust
Foams
- Whipped cream
- Shaving cream
- Marshmallows
- Styrofoam
Emulsions
- Milk
- Mayonnaise
- Lotion
Gels
- Gelatin
- Butter
- Jelly
Sols
- Ink
- Rubber
- Shampoo
- Liquid detergent
What You Need To Know About Colloid
- A colloid is a mixture with particles ranging between 1 and 1000 nanometers in diameter and still able to remain evenly distributed throughout the solution. In colloids the substances remain dispersed and do not settle to the bottom of the container.
- The particles in the colloidal solution are visible through the electron microscope but cannot be seen with a naked eye.
- The particles of the colloidal solutions do not diffuse or pass through parchment paper but it easy through filter paper.
- The particle size in colloid is between 1-100nm.
- The colloid is a form of a homogenous solution.
- Particles of colloids do not undergo sedimentation. Particles do not separate.
- Colloids show Tyndall Effect (scatters light).
- Particles in the colloidal solution show Brownian movements.
What Is A Suspension?
A suspension is a heterogeneous mixture in which some of the particles out of the mixture upon standing. In order for liquid to be a suspension, the particles must not dissolve in the fluid. The particles in a suspension are far larger than those of a solution; therefore gravity is able to pull them down out of the dispersion medium (water).
Suspensions are made of two different phases of matter mixed together. It can be a solid mixed into a liquid, a gas mixed into a liquid and any other combination of two phases. More importantly, suspensions are typically cloudy and you can’t see through them.
Unlike colloids, the dispersed particles in a suspension can be separated from the dispersed medium by filtering. Generally, suspensions are categorized as heterogeneous because the different substances in the mixture will not remain uniformly distributed if they are not actively being mixed.
It is also important to note that, suspensions may scatter light, but if the number of suspended particles are sufficiently large, the suspension may simply be opaque and the light scattering will not occur.
Examples Of Suspension
- Sand in water
- Powdered chalk in water
- Mercury in oil
- Soot in air
- Flour in water
- Slaked lime for whitewashing
- Paints in which dyes are suspended in turpentine oil
- Milk of magnesia
What You Need To Know About Suspension
- A suspension is a heterogeneous mixture in which some of the particles settle out of the mixture upon standing.
- The particles in the suspension can be seen with a naked eye as well as under the electron microscope.
- The suspension particles cannot pass through parchment or filter paper.
- The suspension has particles size above 100 nm.
- The suspension is a form of heterogeneous solution.
- The particles of suspensions undergo sedimentation.
- The particles show Tyndall effect (scatter light).
- The particles in suspension show Brownian movements.
Difference Between Colloid And Suspension In Tabular Form
| BASIS OF COMPARISON | COLLOID | SUSPENSION |
| Description | A colloid is a mixture with particles ranging between 1 and 1000 nanometers in diameter and still able to remain evenly distributed throughout the solution. | A suspension is a heterogeneous mixture in which some of the particles settle out of the mixture upon standing. |
| Particle Visibility | The particles in the colloidal solution are visible through the electron microscope but cannot be seen with a naked eye. | The particles in the suspension can be seen with a naked eye as well as under the electron microscope. |
| Filtration | The particles of the colloidal solutions do not diffuse or pass through parchment paper but it easy through filter paper. | The suspension particles cannot pass through parchment or filter paper. |
| Particle Size | The particle size in colloid is between 1-100nm. | The suspension has particles size above 100 nm. |
| Classification | The colloid is a form of a homogenous solution. | The suspension is a form of heterogeneous solution. |
| Sedimentation | Particles of colloids do not undergo sedimentation. Particles do not separate. | The particles of suspensions undergo sedimentation. |
| Tyndall Effect | Colloids show Tyndall Effect (scatters light). | The particles show Tyndall effect (scatter light). |
| Brownian Movement | Particles in the colloidal solution show Brownian movements. | The particles in suspension show Brownian movements. |