Data were collected for Trial 1 to determine the molar mass of a nonvolatile solid solute when dissolved in cyclo-
hexane. Complete the table for the analysis (See Report Sheet). Record calculated values with the correct number
of significant figures.
B. Freezing Point of Cyclohexane plus Calculation Zone
Unknown Solute
2. Mass of cyclohexane (g) _______
3. Mass of added solute (g) _______
C. Calculations
1. kf for cyclohexane (ºC • kg/mol) _______
2. Freezing point change, ∆T f (ºC) _______
3. Mass of cyclohexane in solution (kg) _______
4. Moles of solute, total (mol)
Show calculation. _______
5. Mass of solute in solution, total (g) _______
6. Molar mass of solute (g/mol)
Show calculation.

To complete the table and perform the required calculations for the molar mass of the solute, I need more specific values for the variables such as mass of cyclohexane, mass of the solute, freezing point depression constant (\(k_f\)), and the temperature change (\( \Delta T_f \)).

However, I can outline the steps and formulas needed to calculate each missing value:

### B. Freezing Point of Cyclohexane plus Calculation Zone

2. **Mass of cyclohexane (g)**: You'll need to measure the mass of the cyclohexane used in the experiment.

3. **Mass of added solute (g)**: This should be the mass of the solute added to the cyclohexane.

### C. Calculations

1. **\(k_f\) for cyclohexane (ºC • kg/mol)**: This is a constant specific to cyclohexane, which can typically be found in reference materials. The value is approximately 20.0 ºC • kg/mol.

2. **Freezing point change, \( \Delta T_f \) (ºC)**: The freezing point depression is the difference between the pure solvent's freezing point and the solution's freezing point.
   \[
   \Delta T_f = T_{\text{freezing, pure solvent}} - T_{\text{freezing, solution}}
   \]
   Record the value from your experimental data.

3. **Mass of cyclohexane in solution (kg)**: Convert the mass of cyclohexane from grams to kilograms:
   \[
   \text{Mass of cyclohexane (kg)} = \frac{\text{Mass of cyclohexane (g)}}{1000}
   \]

4. **Moles of solute, total (mol)**: The number of moles of solute can be calculated using the freezing point depression formula:
   \[
   \Delta T_f = k_f \times m
   \]
   where \(m\) is the molality (moles of solute per kilogram of solvent). Rearranging this to solve for moles of solute:
   \[
   \text{Moles of solute} = \frac{\Delta T_f \times \text{Mass of cyclohexane (kg)}}{k_f}
   \]

5. **Mass of solute in solution, total (g)**: This is the mass of the solute that you added to the cyclohexane.

6. **Molar mass of solute (g/mol)**: Once you know the mass and the moles of the solute, you can calculate the molar mass:
   \[
   \text{Molar mass (g/mol)} = \frac{\text{Mass of solute (g)}}{\text{Moles of solute (mol)}}
   \]

### Example Calculation:

Let's assume the following values for illustration:
- Mass of cyclohexane: 100 g
- Mass of solute: 5 g
- \( k_f \) for cyclohexane: 20.0 ºC • kg/mol
- \( \Delta T_f \): 3.0 ºC

1. Convert mass of cyclohexane to kg:
   \[
   \text{Mass of cyclohexane} = \frac{100 \, \text{g}}{1000} = 0.1 \, \text{kg}
   \]

2. Calculate the moles of solute:
   \[
   \text{Moles of solute} = \frac{3.0 \, \text{ºC} \times 0.1 \, \text{kg}}{20.0 \, \text{ºC • kg/mol}} = 0.015 \, \text{mol}
   \]

3. Calculate the molar mass:
   \[
   \text{Molar mass} = \frac{5 \, \text{g}}{0.015 \, \text{mol}} = 333.33 \, \text{g/mol}
   \]

Would you like to provide specific values so I can assist with the exact calculations?

### Five Related Questions:
1. How does the value of \(k_f\) vary among different solvents?
2. What factors can affect the accuracy of freezing point depression measurements?
3. How is freezing point depression related to colligative properties?
4. What are common errors in determining the molar mass of a solute using this method?
5. How does the molecular weight of a solute affect the freezing point of the solution?

### Tip:
Always ensure that the temperature change (\( \Delta T_f \)) is measured accurately, as small errors can significantly affect the calculated molar mass.

Data were collected for Trial 1 to determine the molar mass of a nonvolatile solid solute when dissolved in cyclohexane. Complete the table for the analysis (See Report Sheet). Record calculated values with the correct number of significant figures.

B. Freezing Point of Cyclohexane plus Calculation Zone
Unknown Solute
2. Mass of cyclohexane (g) _______
3. Mass of added solute (g) _______
C. Calculations
1. kf for cyclohexane (ºC • kg/mol) _______
2. Freezing point change, ∆Tf (ºC) _______
3. Mass of cyclohexane in solution (kg) _______
4. Moles of solute, total (mol)
Show calculation. _______
5. Mass of solute in solution, total (g) _______
6. Molar mass of solute (g/mol)
Show calculation.

Learn how to calculate the molar mass of a solute using freezing point depression in cyclohexane. Understand key concepts such as molality, freezing point depression constant (kf), and step-by-step calculations for moles of solute and molar mass. Ideal for undergraduate chemistry students.

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