Chemistry — Definition

Definition

Chemistry studies the composition, properties and transformations of matter. For UPSC, its value lies in explaining familiar processes: why iron rusts, why dissolved salts conduct electricity, how a metal can displace another from a solution and why a balanced equation conserves atoms.

A chemical explanation connects an observable change to the substances and particles involved. It differs from simply naming a product or recalling an industrial use. The same reasoning helps evaluate claims about materials, pollution and resource extraction, provided the relevant conditions and the difference between a physical change and a chemical reaction remain explicit.