Molarity? Molality?
Wednesday April 28, 2004
Units of chemistry are case-sensitive! A 6 M solution of a compound refers to a 6 Molar dilution, which has a concentration of 6 moles soluter per liter of solution. A 6 m solution refers to a 6 molal dilution, which has a concentration of 6 moles of solute per kilogram of solution. Molarity and molality may be equivalent in some situations, especially if the solvent used to make the solution is water (where a liter weighs about a kilogram). However, the terms and the solutions aren't usually interchangeable. Here's a handy reference defining the units of concentration and here's a set of worked example problems for molarity.
Comments
there is a mistake in your definition of molality on this page: molality is definded per kg of solvent and NOT per kg of solution !
Yeah, Ranier is right, its
m= Moles of Solute/ Lg pf SOLVENT (not solution)
water is usally use as a solution but not at all times because water can be use as a solvent. therefore we can conclude that molality can be defined as solute per solution if you will use water as your solvent because water is usually use as a solution. Ms. Anne is right that molarity and molality maybe equivalent in some situation particularly in water. Can we now say that molality can be defined as solute per solution? Yes it is!!!but not at all times in all situation. got it rainer and DEW72?