How can you convert between molarity and molality?

1 Answer
May 21, 2018

Answer:

The solution density is required....

Explanation:

By definition, #"molarity"="moles of solute"/"volume of solution"#...and thus the units of #"molarity"# are #mol*L^-1#. On the other hand, #"molality"="moles of solute"/"kilograms of solvent"#...and thus #"molality"# is temperature independent given that mass, unlike volume, is UNAFFECTED by ambient pressure.

For dilute AQUEOUS solutions....#"molality"~="molarity"#.

In other scenarios, we need the solution density to calculate one from t'other, and vicey versy...