Science, Tech, Math › Science Dynamic Equilibrium Definition (Chemistry) Share Flipboard Email Print The rates of the forward and reverse reactions are equal at dynamic equilibrium. Rafe Swan, 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 March 08, 2019 A dynamic equilibrium is a chemical equilibrium between a forward reaction and the reverse reaction where the rate of the reactions are equal. At this point, the ratio between reactants and products remains unchanged over time. For elementary reaction, the equilibrium constant may be expressed in terms of the rate constant. For the reaction: A ⇌ B The equilibrium constant K is: K = [B]eq / [A]eq Source Atkins, P.W.; de Paula, J. (2006). Physical Chemistry (8th. ed.). Oxford University Press. ISBN 0-19-870072-5.