Math Problem Statement

The freezing-point depression for a given aqueous solution is0.32K. The freezing-point depression constant for water is 1.86 K/m. Calculate the molality of solutes in the solution.

The equation for freezing point depression is

ΔTf = Kf · m

where ΔTf is the freezing point depression, Kf is the freezing-point depression constant, and m is the total molality of all solutes in solution.

Solution

To calculate the molality of solutes in the solution, we can use the provided freezing point depression equation:

ΔTf=Kfm\Delta T_f = K_f \cdot m

Where:

  • ΔTf\Delta T_f is the freezing point depression,
  • KfK_f is the freezing-point depression constant,
  • mm is the molality of the solution.

Given values:

  • ΔTf=0.32K\Delta T_f = 0.32 \, \text{K},
  • Kf=1.86K/mK_f = 1.86 \, \text{K/m}.

Now, we can rearrange the equation to solve for molality (mm):

m=ΔTfKfm = \frac{\Delta T_f}{K_f}

Substituting the given values:

m=0.32K1.86K/mm = \frac{0.32 \, \text{K}}{1.86 \, \text{K/m}}

Let's calculate the molality:

m=0.321.86m = \frac{0.32}{1.86}The molality of the solutes in the solution is approximately 0.172mol/kg0.172 \, \text{mol/kg}.

Would you like further details or have any questions? Here are some related topics:

  1. How does molality differ from molarity?
  2. What factors affect freezing-point depression in a solution?
  3. Can you explain why freezing-point depression occurs at the molecular level?
  4. How would you calculate the mass of a solute needed to achieve a specific molality?
  5. How does the presence of multiple solutes affect the freezing point of a solution?

Tip: Molality is temperature-independent because it's based on the mass of the solvent, not the volume, which makes it particularly useful in freezing-point depression and boiling-point elevation calculations.

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Math Problem Analysis

Mathematical Concepts

Freezing point depression
Molality

Formulas

ΔTf = Kf * m

Theorems

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Suitable Grade Level

High School