Solubility, Solvents and Solutes

From this concept, the students will get an idea about solutes and solvents and how a solution is formed.

After reading the concept, students will be able to:

Know what is solute and solvent.
Understand the difference between a dilute solution and a concentrated solution.
Analyse what an aqueous solution and a non-aqueous solution are.
Know what is supersaturated solution.
Analyse the factors affecting solubility in a solution.
Define precipitate and supernatant in a saturated solution.

Each concept is explained to class 4 students using descriptions, illustrations, and concept maps. After you go through a concept, assess your learning by solving the two printable worksheets given at the end of the page.

Download the worksheets and check your answers with the worksheet solutions for the concept of Solutes and Solvent provided in PDF format.

What Is a Solution?

When two or more substances mix to make a homogenous mixture, it is called a solution. A solution is made up of two components—the solvent and the solute.

Examples: Take some water in a glass and add a spoonful of sugar to it. Stir it thoroughly, and after some time, the sugar will disappear and will result in the formation of a solution of sugar and water.

You would not be able to see the sugar in the water because the sugar has completely dissolved in the water.

What is a Solvent?

It is the substance in which a solute dissolves; or in other words, a solvent is a component present in the larger amount in a solution. In the above-mentioned example, water is the solvent.

What is a Solute?

It is the substance that is dissolved in a solution; or in other words, a solute is a component present in a smaller amount in a solution.

Both solutes and solvents could be gases, liquids, or solids and can combine to make a solution.

Relation Between Solutes, Solvents, and Solutions:

Examples of Different Solutions:

Type	Solvent	Solute	Solution
Gas/gas	Nitrogen	Oxygen	Air
Gas/liquid	Water	Carbon dioxide	Soda drink
Liquid/liquid	Water	Alcohol	Beer
Solid/liquid	Water	Salts	Seawater

Types of Solutions:

Based on different factors, solutions can be classified into different groups.

According to the nature of the solvents, solutions can be of two types—aqueous solutions and non-aqueous solutions.

1. Aqueous Solutions: When a solute is dissolved in water, it is called an aqueous solution.

Example: Dissolving sugar in water.

2. Non-aqueous Solutions: When a solute is dissolved in any kind of solvent, except water, it is called a non-aqueous solution.

Example: Iodine dissolved in carbon tetrachloride.

According to the ability to dissolve, solutions can be of three types—saturated, unsaturated, and supersaturated.

1. Saturated Solutions: When the solvent of the solution cannot dissolve any more solute, it is called a saturated solution.

2. Unsaturated Solutions: When the solvent of a solution can dissolve more amount of solute, it is called an unsaturated solution.

3. Supersaturated Solutions: A solution that contains more than the maximum amount of solute that is capable of being dissolved at a given temperature is called a supersaturated solution.

According to the amount of solute present, solutions can be of two types—dilute and concentrated solutions.

1. Dilute Solutions: When a small amount of solute is dissolved in a large amount of solvent, it is called a dilute solution.

2. Concentrated Solution: When a large amount of solute is dissolved in a relatively small amount of solvent, it is called a concentrated solution.

Solubility:

It is the maximum amount of a solute that will dissolve in a given amount of solvent at a particular temperature.

The solvent in the right glass tube cannot dissolve any more solute since the solute has started to settle at the bottom of the glass tube. It is called the precipitate. The rest of the solution is called the supernate.

According to solubility, we can divide solutions into three types—

Unsaturated solution
Saturated solution
Supersaturated solution

These have already been discussed above.

Effect of Temperature on Solubility:

A solution becomes saturated only at a particular temperature.
When a saturated solution is heated to a higher temperature, it becomes unsaturated.
As the temperature of the solution rises, the solute’s solubility increases and more solute can be dissolved in the solution.
If a saturated solution at a given temperature is cooled to a lower temperature, some of its dissolved solutes will separate as solid crystals.
It happens because the solubility of the solute in the solution decreases as temperature decreases.

New Words:

Precipitate: The substance that deposits in solid form in a solution at the bottom of the container is called the precipitate.

Supernate: The liquid that is found above a precipitate or sediment in a solution is called supernate.

Did You Know?

Solutions can be either heterogeneous or homogenous. Heterogenous solutions have a non-uniform composition and properties throughout the solution.
Example: Solution of oil and water, water and sand, water and chalk powder.
Homogenous mixtures have a uniform composition.
Example: Alcohol in water.