What is the difference between molarity and molality?

Molality is moles of solute per kilogram of solvent. Molarity is moles of solute per liter of solution. Molalities are more convenient than molarities in experiments that involve significant temperature changes. Because the volume of a solution increases when its temperature increases, heating makes the solutions molarity go down- but the molality, which is based on masses rather than volumes, remains unchanged.

Author: Fred Senese senese@antoine.frostburg.edu

Copyright © 1997-2010 by Fred Senese
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Last Revised 02/23/18.URL: http://antoine.frostburg.edu/chem/senese/101/solutions/faq/molality-vs-molarity.shtml