Substance

Chemical Substance

A substance or chemical substance in chemistry or chemical science is a unique form of matter (solid, liquid, gas, plasma) having a definite composition, properties, and structure. All objects or everything in our universe are made up of chemical substances. Therefore, the air we breathe, the food we eat, stones, clouds, stars, plants, and animals everything are examples of chemical substances.

Chemical substances are formed by a single element or chemical compound or a mixture of non-reacting molecules. Pure water (H₂O) is an example of a chemical substance formed by one oxygen and two hydrogen atoms. Therefore, the atomic ratio in a pure water molecule is always 2:1. Other common substances are diamond, table salt, refined sugar, alcohol, benzene, a mixture of gases, and metals like iron, copper, aluminum, gold, silver, etc.

Chemical Substance Examples

A chemical substance occurs in nature at different states or phases such as solid, liquid, gas, and plasma. However, different forms of substances are interchangeable from one state to another by changing temperature or pressure. Examples of solid, liquid, and gaseous substances are:

• Solid: Sugar, sands, rocks, stones, metals like iron, copper, aluminum, gold, silver, etc.
• Liquid: Water, milk, juice, oil, kerosene, petrol, alcohol, benzene, etc.
• Gaseous: Mixture of gases (oxygen, nitrogen, carbon dioxide, inert gases, etc. Other gases such as hydrogen, ammonia, nitrogen dioxide, water vapour, sulfur dioxide, etc.

In this part of online learning chemistry, we study different articles or topics related to the properties, composition, structure, production, and uses of a chemical substance.