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.

Nov 25, 2017

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

Explanation:

We know the T_f = 0°C for water.

Hence, $\Delta {T}_{f} = 2.25$. Moreover, nonvolatile solutes' van't Hoff factor is generally 1.

And, $\Delta {T}_{f} = i {K}_{f} m$

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

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