[Chemistry Class Notes] on Suspensions Pdf for Exam

Take a glass of water and add a tablespoon of flour to it. Now stir it well. What do you see? Does the water and flour mixture appear clear or turbid (unclear)? Yes, you are right. The mixture appears turbid. What do you think, what have you prepared? A solution, a colloid or a suspension? Well if you observe this mixture for some more time then you will see that particles of flour slowly settle down at the bottom of the glass. This indicates that it is a suspension. We will discuss suspensions in detail from a chemistry point of view. With this, we will discuss solutions, colloids, and solubility as well in comparison with suspensions. So that it will help you to distinguish mixtures as suspension, solution, or colloids.

 

What is Suspension? 

A suspension is a heterogeneous mixture in which the solute particles do not dissolve but remain suspended throughout the bulk of the medium. In other words, suspensions are non – homogeneous systems in which solids are dispersed in liquids. Constituent particles of a suspension are large enough that gravity can pull them down out of the dispersion medium. These particles can be easily separated by the filtration method from the dispersion medium. The size of particles in suspension is at least 100 times larger than particles of solution. 

Examples of Suspension 

Some common examples of suspension are listed below –

• Mixture of flour and water

• Mixture of chalk and water

• Muddy water

• Mixture of sand and water

• Paints (water-based)

• Mixture of Slaked lime (Calcium hydroxide) in water 

• Mixture of magnesium hydroxide and water (Milk of Magnesia)

• Lemonade 

• Some salad dressings such as thousand island, honey mustard dressing

• Sattu sharbat 

Properties of Suspension 

General characteristics and properties of suspensions are listed below –

• It is a heterogeneous mixture.

• Constituent particles of the suspension mixture can be seen by naked eyes. 

• The size of particles in suspension is more than 100 nm. 

• Suspension shows the Tyndall effect. It means particles of a suspension scatter a beam of light passing through it and making its path visible. 

• If the suspension is left undisturbed, its particles settle down. It shows that suspension is an unstable mixture. In this condition, the suspension does not show the Tyndall effect. 

• Constituent particles of a suspension can be separated by filtration. 

What is a Solution?  

A solution is a homogeneous mixture of two or more substances. A solution has a solute and solvent as its components. The component of the solution which dissolves the other component in it is called solvent while the other component which gets dissolved in the solvent is called the solute. Generally, in a solution solute is present in a lesser amount than solvent. 

Examples of Solutions 

You can see many examples of solutions in your daily life. A few examples of solutions are listed below –

• Mixture of sugar and water.

• Tincture of iodine (solution of iodine in alcohol)

• Soda water 

• Air (a homogeneous solution of various gasses)

• Alloys (Mixture of two or more metals or a metal and a non – metal which cannot be separated by physical methods. For example – Brass, Stainless steel etc.)

Properties of Solution 

Solution shows the following properties –

• It is a homogeneous mixture.

• The size of the particles in the solution is less than 1 nm in diameter. 

• Particles of the solution cannot be seen by naked eyes. 

• Particles of solution cannot be separated by simple physical methods of separation such as filtration.

Some common examples of colloids are listed below in tabular form with their dispersion phase, dispersion medium and type –

Examples of Colloids

 

 

Properties of a Colloid 

Properties of Colloids are listed below –

• A colloid is a heterogeneous mixture. 

• Particles of colloids are not visible by naked eyes.

• In colloids, dispersed phase particles have a diameter between 1 – 100 nm (approximately). 

• They show the Tyndall effect.

• In colloids, dispersed particles do not settle down when left undisturbed.

• Colloids are stable mixtures.

• In colloids, the dispersed phase and dispersion medium cannot be separated by filtration. 

• In colloids, dispersed particles show Brownian movement. 

Comparison between properties of suspension, colloids and solution is given below in tabular form for your better conceptual clarity –

Difference between Suspension, Colloids and Solution