Introduction and What is a Mixture?

You probably come across one or other forms of a mixture in your daily life. The air that you breathe is the commonest example of a mixture. Did you know that? Today, we will look at greater depths into the impure substances or mixtures, as they are commonly called. In addition to a general introduction, let us discuss all the types and properties of them in this chapter.

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Classification of Matter

First of all, you already know, you can classify matter into two types:

• Pure substances: These are again classified into elements and compounds.
• Impure substances: All mixtures are considered to be impure substances.

What is a Mixture?

The majority of substances that we see in our surrounding neighborhoods are actually not pure substances. They are all mixtures! Therefore, what are they?

Mixtures are substances composed of two or more forms of matter. You can separate them by physical methods. Examples include a solution of salt and water, a mixture of sugar and water, different gases, air, etc. In any mixture, the various components do not combine through any kind of chemical changes. Therefore, the components do not lose their individual properties.

What is solution ?

Types of Mixtures

Based on their composition, they can be divided into two types:

• Homogeneous
• Heterogeneous

Homogeneous Mixture

Mixtures having a uniform composition throughout their bodies are called Homogeneous Mixtures. For example – a mixture of salt and water, a mixture of sugar and water, air, lemonade, soda water, etc. Here, a mixture of salt in water is a classic example. This is because here, the boundary, between salt and water can never be differentiated. When a ray of light is passed through the mixture of salt and water, the path of light is not seen.

Properties

• All solutions are examples of a homogeneous mixture.
• The particles in such a case are less the one nanometer.
• They do not show a Tyndall effect.
• You cannot differentiate the boundaries of particles.
• You cannot separate the constituent particles here using centrifugation or decantation.
• Alloys are examples of a solution.

Want to know more about Concentration Of Solution?

Heterogeneous Mixture

Mixtures lacking a uniform composition throughout are called Heterogeneous Mixture. Therefore,  a mixture of soil and sand, sulfur and iron filings, oil and water, etc. are heterogeneous as they do not have a uniform composition. You can identify the various boundaries of the constituent particles of a homogeneous mixture. This is because in such a case it has two or more distinct phases.

Properties

• Most of the mixtures are heterogeneous except solutions and alloys.
• The constituent particles are present uniformly here.
• You can identify the components easily.
• Generally, two or more phases are present in a heterogeneous mixture.
• The size of the particles here is between one nanometer and one micrometer.
• They show a Tyndall effect.

Question For You

Q. Define the types of mixtures.

Ans: Based on their composition, you can classify them into two major types:

• Homogenous mixtures: These are the ones having a uniform composition throughout their bodies. Examples are a mixture of salt and water, sugar, and water, air, lemonade, soda water, etc.
• Heterogeneous Mixtures: These are the ones that lack uniform composition throughout. Hence, a mixture of soil and sand, sulfur and iron filings, oil and water, etc.