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**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 (C _{6}H_{12}O_{6}) 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 (ΔT_{f})** is given by:

$\overline{){{\mathbf{\Delta T}}}_{{\mathbf{f}}}{\mathbf{=}}{{\mathbf{T}}}_{\mathbf{f}\mathbf{,}\mathbf{}\mathbf{pure}\mathbf{}\mathbf{solvent}}{\mathbf{-}}{{\mathbf{T}}}_{\mathbf{f}\mathbf{,}\mathbf{}\mathbf{solution}}}$

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)

**K _{f}** = freezing point depression constant (in ˚C/m)

Recall that the ** molality of a solution** is given by:

$\overline{){\mathbf{molality}}{\mathbf{=}}\frac{\mathbf{moles}\mathbf{}\mathbf{solute}}{\mathbf{kg}\mathbf{}\mathbf{solvent}}}$

**For this problem, we need to do the following:**

* Step 1:* Calculate for ΔT

_{f}.

* Step 2:* Determine the molality of the solution.

* Step 3:* Calculate the mass of glucose (C

_{6}H

_{12}O

_{6}) needed.

###### Problem Details

What mass of glucose (C_{6}H_{12}O_{6}) should be dissolved in 10.0 kg of water to obtain a solution with a freezing point of -4.2 ^{o}C?

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Freezing Point Depression concept. You can view video lessons to learn Freezing Point Depression Or if you need more Freezing Point Depression practice, you can also practice Freezing Point Depression practice problems .

What professor is this problem relevant for?

Based on our data, we think this problem is relevant for Professor Ratliff's class at USF.