The branch of science that studies chemicals and their properties is called chemistry. This field investigates the composition, structure, behavior, and changes of matter through various sub-disciplines including organic, inorganic, physical, and analytical chemistry. Chemistry plays a crucial role in understanding biological processes, developing materials, and advancing technologies. Through experimentation and the scientific method, chemists seek to uncover the underlying principles that govern chemical interactions, driving innovation in areas like medicine, environmental science, and industry.