Surface chemistry is the study of chemical reactions and processes that occur at the interface between different phases, such as solid-liquid, solid-gas, or liquid-gas. It focuses on how molecules interact with surfaces, which can significantly influence properties like adhesion, catalysis, and corrosion. Understanding these interactions is crucial in fields like materials science, nanotechnology, and environmental science. Key concepts in surface chemistry include adsorption, where molecules adhere to a surface, and catalysis, where a surface facilitates a chemical reaction. Techniques such as scanning tunneling microscopy and X-ray photoelectron spectroscopy are often used to analyze surface properties and behaviors, providing insights into how surfaces can be engineered for specific applications.