Science, Tech, Math › Science Molar Enthalpy of Fusion Definition Share Flipboard Email Print Molar enthalpy of fusion is the energy absorbed to melt one mole of solid into a liquid. Roelinda Tip / EyeEm, Getty Imags 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 July 11, 2019 Molar enthalpy of fusion is the amount of energy needed to change one mole of a substance from the solid phase to the liquid phase at constant temperature and pressure. It is also known as the molar heat of fusion or latent heat of fusion. Molar enthalpy of fusion is expressed in units of kilojoules per mole (kJ/mol). Finding Molar Enthalpy of Fusion One method of finding molar enthalpy of fusion is experimentally using a calorimeter. The other method is to consult a table of the molar enthalpies of selected substances. A table usually includes the molar enthalpies of vaporization and fusion. Usually the pressure is 1 atm (101.325), unless otherwise stated.