Matter and its Classification

In this post, we will discuss about matter and its classification.

What is matter?

Matter is the material of which the universe is composed. Matter may be defined as something that occupies space, have mass and offers resistance to any force applied on it.

For ex: Air, Water, Ice, Milk, Oil, Petrol, etc.

What are the characteristics of particles of matter?

The characteristics of particles of matter are as follows:

• All forms of matter consists of very tiny particles. That is, all forms of matter are particulates in nature.
• The particles of matter are very small. The size however varies from one form of matter to another.
• The particles have spaces, called void spaces, in between them.
• The particles are constantly in motion.
• The particles of matter attract each other. The formation of huge rocks is due to force of attraction between the particles.

Classification of matter

A complete classification of matter into two fundamental groups was and also is a difficult task. On the basis of chemical composition, the matter exist either as a single substance or as a mixture containing two or more substances, which are known to be as pure substance or mixture respectively.

A sample of matter containing only one substance is called a pure substance or simply as a substance.

A sample of matter containing two or more substances is called a mixture. A mixture may contain two or more substances.

What is a substance?

A substance may be defined as the kind of matter which cannot be separated into other kinds of matter by any physical process is called a substance.

For instance, iron, sucrose, water, sodium chloride, etc. are substances. The composition of a substance is the same throughout even at the atomic or molecular level.

What are the characteristics of substances?

A substance shows the following characteristics:

(a) A substance can contains only one kind of atom or molecule.

(b) A substance is perfectly homogeneous.

(c) A substance has a definite composition which does not change with time.

(d) A substance has definite melting point, boiling point, density, etc.

Pure substances can be further classified into: 

(a) Elements                            (b) Compounds

How to check the purity of a substance?

Each substance has definite melting point, boiling point, density, refractive index, etc. These properties are very sensitive to the impurities. Therefore, the purity of any substance can be checked by determining its melting and boiling point or any other property.

What is mixture?

A mixture is defined as follows:

A mixture is that form of matter in which two or more substances (elements or compounds) are present in any proportion.

For example, air is a mixture containing mainly oxygen, nitrogen, smaller amounts of carbon dioxide, dust particles, etc.

Substances present in a mixture are called components or constituents of the mixture, e.g., in a mixture of salt and sugar, the constituents or components are salt and sugar.

What are the various type of mixtures?

Depending upon the nature of substances present in any mixture, it can be classified into two following types:

(a) Homogeneous mixture (b) Heterogeneous mixture

Homogeneous mixture

A mixture which is perfectly uniform in composition and properties throughout its bulk is called homogeneous mixture. For example, solution of common salt in water, solution of sugar in water, solution of alcohol in water, dust free air are some common homogeneous mixture. Kerosene is a homogeneous mixture of many hydrocarbons. Some common alloys (e.g., bronze, brass, etc) are also homogeneous mixture.

Homogeneous mixture has one phase only.

Heterogeneous mixture

A mixture which has different composition and different properties at different locations in the mixture is called a heterogeneous mixture.

For example, muddy water from a pond, mixture containing sugar and sand are heterogeneous mixtures, mixture consisting of sodium chloride and iron powder or fillings, mixture consisting of common salt and sulphur.

Heterogeneous mixture has more than one phase.

What are the characteristics of a mixture?

Mixtures show the following characteristics:

(a) In mixtures, the constituent may be present in any proportion.

(b) Mixtures show the properties of all the constituents present therein, e.g., a mixture containing sugar and salt will be salty-sweet.

(c) During the preparation of a mixture, very little or no energy such as heat, light and electricity is either absorbed or evolved.

(d) Mixtures, except solutions, are heterogeneous.

(e) The components of a mixture can be separated by simple physical methods.

A mixture containing potassium nitrate, sulphur and charcoal is called gun powder.

Read More: Is Matter Around Us Pure?

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