Importance of Chemistry Chemistry is an important branch of science. Chemistry deals with the matter that form our environment and the transformation that the matter undergoes. Chemistry is therefore, useful in understanding the changes taking place in the constituents of the environment and the resulting advantages. Chemistry is connected with composition, structure and properties of the matter. In fact it is a science of atoms and molecules. Organic chemistry, inorganic chemistry, physical chemistry, analytical chemistry, industrial chemistry and biochemistry are various branches of chemistry. Chemistry deals with compounds of atoms and their properties. We can understand how the compounds are formed by the forces between the atoms. Nature produces large number of compounds, while laboratories synthesize many new compounds. Chemistry is concerned with studying the properties of all these new compounds. The studies in chemistry in modern times has been greatly facilitated because of effective inter-linking of numerous facts and principles established from it. If any interrelated relationship is observed among many established facts it is explained by a mathematical equation. Such a relation or mathematical equation is called pro-principle. Such a proprinciple is termed 'principle' or law if it is found to be true when tested by several tests under different conditions. At every stage in life, we are connected with different aspects of chemistry directly or indirectly. Chemistry encirc{les} variety of fields, e.g., agriculture, food, medicines, fertilisers, alkalies, acids, salts, dyes, different polymers, soaps, detergents, metals, mixed-metals, samples of atmospheres, functioning of the minds and computer reactions. Thus, the knowledge of chemistry, in reality, is useful in different aspects of human life as well as in some destructive aspects.
Physical Quantities and SI Units
He value of a physical quantity is always