Solutions And Suspensions

In this article, the following are the objectives that will be discussed.

• Understand that solutions and suspensions are mixtures. 
• Distinguish between solute, solvent and solution.
• State the factors affecting solubility.
• State the factors affecting the rate of dissolving.

Types of Mixtures

The two types of mixtures are Solutions and Suspensions.          

An example of a solution is vinegar and an example of a suspension is oil salad dressing.

Solutions

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What are solutions?

A solution is a homogeneous mixture, where the particles are evenly distributed. Hence, a solution has a uniform appearance and composition throughout.

A solution is made up of a solute and a solvent.

A solute is a substance that dissolves in a solvent (e.g. salt).

A solvent is a substance that dissolves the solute (e.g. water).

Properties of Solutions

1. The solutes in solutions are very small particles.
2. Solutions are clear and transparent.
3. The solute particles in a solution do not settle down to the bottom of the beaker when left undisturbed.
4. No residue is left after filtering a solution.

Suspensions

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What are suspensions?

A suspension is a mixture in which insoluble substances are suspended in a liquid or gas. It is a heterogeneous mixture, where the particles are not evenly distributed. Hence, a suspension does not have a uniform appearance and composition.

Properties of Suspensions

1. The solutes of suspensions are large and insoluble particles.
2. Suspensions are opaque.
3. The solute particles in a suspension settle down after some time when left undisturbed.
4. The residue is left on the filter paper after filtering a suspension.

Solubility

Solubility is the ability of a solute to dissolve in a solvent.

Factors affecting Solubility:

• Nature of solvent
• Nature of solute
• Temperature

Rate of Dissolving

The rate of dissolving is the amount of solute that dissolves in a fixed amount of solvent, given a fixed amount of time.

Factors affecting the Rate of Dissolving:

• Size of solute particles
• Rate of stirring
• Temperature

Revision Questions

Here are some questions for us to look into, based on the objectives of this article.

Question 1:

Which of the following explains how suspensions are formed?

1. Compounds that are chemically combined
2. Elements that are chemically combined
3. Substances that dissolve in a liquid
4. Substances that do not dissolve in a liquid 

Solution:

(D) Substances that do not dissolve in a liquid 

Explanation:

A suspension is a mixture in which insoluble substances are suspended in a liquid or gas.

Question 2:

Which of the following explains the rate of dissolving of a solute?

1. How much a solute dissolves in a fixed volume of solvent
2. How much a solute dissolves in any volume of solvent
3. How fast a solute dissolves in a fixed volume of solvent
4. How fast a solute dissolves in any volume of solvent

Solution: 

(C) How fast a solute dissolves in a fixed volume of solvent

Explanation:

The rate of dissolving is the amount of solute that dissolves in a fixed amount of solvent, given a fixed amount of time. 

Question 3:

Which of the following word equations is correct?

1. solute + solute → solution
2. solution + solvent → solute
3. solute + solution → solvent
4. solvent + solute → solution

Solution:

(D) solvent + solute → solution

Explanation:

A solution is where the solute dissolves in a solvent.

Question 4:

Which of the following affects the solubility of a solute?

1. Nature of solute
2. Rate of stirring
3. Temperature of solvent

Choose the correct option
 

1. I and II only
2. I and III only
3. II and III only
4. All of the above

Solution: 

(B) I and III only

Explanation:

Solubility is the ability of a solute to dissolve in a solvent.

The factors that affect the solubility of a solute are:

1. nature of solute;
2. nature of solvent; and
3. temperature.