Science, Tech, Math › Science Heterogeneous Reaction Definition Share Flipboard Email Print Juan Carlos Juarez Jaramillo / Getty Images Science Chemistry Chemical Laws Basics Molecules Periodic Table Projects & Experiments Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated January 11, 2020 A heterogeneous reaction is a chemical reaction where the reactants are in different phases from each other. In a homogeneous reaction, the reactants are in the same phase as one another. Examples The reaction between acid and metal is a heterogeneous reaction. A reaction between a gas and a liquid, as between air and seawater, is heterogeneous. A reaction at the surface of a catalyst is heterogeneous. In contrast, a reaction between two miscible liquids or between two gases is homogeneous. Sources Guéguen, Yves; Palciauskas, Victor (May 1994). Introduction to the Physics of Rocks. Princeton University Press. ISBN 978-0-691-03452-2.