Physical chemistry is a branch of chemistry that combines principles of physics and chemistry to study how matter behaves on a molecular and atomic level. It focuses on understanding the physical properties of molecules, the forces that act between them, and how these interactions influence chemical reactions. This field often employs mathematical models and experimental techniques to explore concepts such as thermodynamics, kinetics, and quantum mechanics. Researchers in physical chemistry investigate various phenomena, including reaction rates, phase transitions, and spectroscopy. By analyzing these processes, they can predict how substances will react under different conditions, which is essential for applications in areas like materials science, biochemistry, and environmental science.