Science, Tech, Math › Science Mole Definition Share Flipboard Email Print artpartner-images, Getty Images Science Chemistry Basics Chemical Laws 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. Updated March 08, 2017 Mole Definition: a chemical mass unit, defined to be 6.022 x 1023molecules, atoms, or some other unit. The mass of a mole is the gram formula mass of a substance.Examples: 1 mole of NH3 has 6.022 x 1023molecules and weighs about 17 grams. 1 mole of copper has 6.022 x 1023atoms and weighs about 63.54 grams.Return to the Chemistry Glossary Index citecite this article Format mla apa chicago Your Citation Helmenstine, Anne Marie, Ph.D. "Mole Definition." ThoughtCo, Feb. 7, 2017, thoughtco.com/mole-definition-in-chemistry-606377. Helmenstine, Anne Marie, Ph.D. (2017, February 7). Mole Definition. Retrieved from https://www.thoughtco.com/mole-definition-in-chemistry-606377 Helmenstine, Anne Marie, Ph.D. "Mole Definition." ThoughtCo. https://www.thoughtco.com/mole-definition-in-chemistry-606377 (accessed April 24, 2018). copy citation Continue Reading