Is Matter Around Us Pure

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• Questions
• Summary

Matters can be classified into two types:

1. Pure substances
2. Impure substances (Mixture)

Pure substances mean that all elements have same chemical properties. A pure substance is made up of the same kind of elements. Pure substances are of two types – Elements and Compounds.

The mixture is a substance in which two or more substances (element or compound) are simply mixed together in any proportion. Examples: The air is a mixture of oxygen, nitrogen, argon, carbon dioxide and water vapour.

Mixtures are of two types on the basis of their composition - Homogeneous mixture and Heterogeneous mixture.

Homogeneous: Mixtures which have a uniform composition throughout are called Homogeneous Mixture. For example – a mixture of salt and water, mixture of sugar and water, air, lemonade, soda water, etc.

It has no visible boundaries of separation between the various constituents.

General Properties of Homogeneous Mixture:

1. All solutions are the examples of a homogeneous mixture.
2. The particles of a homogeneous mixture are less the one nanometer.
3. A homogenous mixture does not show Tyndall effect.
4. The boundaries of particles cannot be differentiated.
5. The constituent particles of the homogenous mixture cannot be separated using centrifugation or decantation.
6. Alloys are the examples of the solution.

Heterogeneous: Mixtures which do not have a uniform composition throughout are called Heterogeneous Mixture. For example – a mixture of soil and sand, a mixture of sulphur and iron fillings, mixture of oil and water etc.

The boundaries of constituent particles of a homogeneous mixture can be identified easily; as a homogeneous mixture has two or more distinct phases.

General Properties of Heterogeneous Mixture:

1. Most of the mixtures are heterogeneous except solutions and alloys.
2. The constituent particles are present uniformly in a heterogeneous mixture.
3. The components of a heterogeneous mixture can be identified easily.
4. Generally, two or more phases are present in a heterogeneous mixture.
5. Particles of a heterogeneous mixture are sized between one nanometer and one micrometre or more.
6. Heterogeneous mixtures show Tyndall effect.