How Do You Calculate Molality From Molarity?
Molarity and molality are often confused. Both are units of concentration used in chemistry, based on the mole. A mole is a fixed number of atoms or molecules that chemists use in measurement, much like bakers use the fixed number called a dozen. Molarity is the number of moles of a solute, or dissolved substance, in one liter of solution. Molality is the number of moles of a solute per kilogram of solvent–the liquid that dissolves the solvent. The difference is subtle and the numbers are usually very similar. Converting between molarity and molality involves a few steps, but it isn’t too complicated. Examine the parameters of the problem you wish to solve. For instance, imagine that you want to know the molality of a 0.5 Molar solution of salt water. The salt is the solute; its chemical formula is NaCl. Determine the density of your solute. Use your balance to measure the mass of your empty graduated cylinder. Then fill the cylinder to the 5 mL mark with your solute and measure its m
