substanser

Substanser, or substances, are forms of matter with a definite composition and characteristic properties. They are distinguished from mixtures by having a fixed ratio of components and a consistent structure. Substanser can be pure, containing a single component, or mixtures of two or more substances that can be separated by physical methods.

Pure substances split into elements and compounds. Elements consist of a single type of atom and cannot be decomposed by chemical means. Compounds are made from two or more elements in fixed proportions and can only be broken down by chemical reactions. Mixtures contain two or more substances physically combined and may be homogeneous or heterogeneous.

Substances have physical properties such as melting point, boiling point, density, color, and state of matter, and chemical properties such as reactivity. Physical changes (like melting) do not alter identity, while chemical changes produce new substances. Conditions like temperature and pressure influence stability and behavior.

Examples include elements such as oxygen and iron; compounds such as water, carbon dioxide and sodium chloride. Air is a mixture of gases; steel is an alloy. Substanser are separated and purified by methods such as distillation, filtration, crystallization, and chromatography.

In science, understanding substances supports chemistry, materials science and pharmacology. Safety and regulation classify many substances by hazard, guiding handling, storage and labeling.