Chemistry is a fundamental natural science dedicated to studying the composition, structure, properties, and reactions of matter. It explores matter at the atomic and molecular levels, examining how substances interact and change form. The field is generally divided into major branches, including organic chemistry, which focuses on compounds containing carbon, and physical chemistry, which relates physical measurements to chemical change. Chemical reactions involve the rearrangement of atoms and the transfer of energy, which forms the basis for understanding material properties, biological processes, and industrial transformations. Understanding these principles is critical for developing new materials, pharmaceuticals, and energy sources.