# Problem: What mass of glucose (C6H12O6) should be dissolved in 10.0 kg of water to obtain a solution with a freezing point of -4.2 oC?

###### FREE Expert Solution

We’re being asked to determine the mass of glucose (C6H12O6) that should be dissolved in 10.0 kg of water to obtain a solution with a freezing point of -4.2˚C.

Recall that the freezing point of a solution is lower than that of the pure solvent and the change in freezing point (ΔT­f) is given by:

The change in freezing point is also related to the molality of the solution:

$\overline{){{\mathbf{\Delta T}}}_{{\mathbf{f}}}{\mathbf{=}}{{\mathbf{imK}}}_{{\mathbf{f}}}}$

where:

i = van’t Hoff factor

m = molality of the solution (in m or mol/kg)

Kf = freezing point depression constant (in ˚C/m)

Recall that the molality of a solution is given by:

For this problem, we need to do the following:

Step 1: Calculate for ΔTf.

Step 2: Determine the molality of the solution.

Step 3: Calculate the mass of glucose (C6H12O6) needed.

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###### Problem Details

What mass of glucose (C6H12O6) should be dissolved in 10.0 kg of water to obtain a solution with a freezing point of -4.2 oC?