What is the molality of a water solution that contains a non-volatile solute and freezes at -2.25 degrees Celsius? The freezing point depression constant for water Kf is 1.86 degrees Celsius per mole.

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Answer 1 · 2017-11-25T23:23:28

The molality of this solution is approximately #1.21m#.

We know the #T_f = 0°C# for water.

Hence, #DeltaT_f = 2.25#. Moreover, nonvolatile solutes' van't Hoff factor is generally 1.

And, #DeltaT_f = iK_fm#

We'll do our calculation given those variables, as such

#2.25°C = 1 * (1.86°C)/(m) * m#
#therefore m = 1.21m#