Depression in Freezing Point given Vapour Pressure Calculator

Depression in Freezing Point Formula:

\[ \Delta T_f = \frac{(P_o^A - P_A) \times [R] \times (T_{fp}^2)}{P_o^A \times \Delta H_{fusion}} \]

Vapour Pressure of Pure Solvent:

Vapour Pressure of Solvent in Solution:

Solvent Freezing Point:

Molar Enthalpy of Fusion:

J/mol

Depression in Freezing Point (K):

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1. What is Depression in Freezing Point?

Definition: The Depression in Freezing Point is the phenomena that describes why adding a solute to a solvent results in the lowering of the freezing point of the solvent.

Purpose: This calculator helps determine how much the freezing point will be lowered based on vapour pressure changes.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ \Delta T_f = \frac{(P_o^A - P_A) \times [R] \times (T_{fp}^2)}{P_o^A \times \Delta H_{fusion}} \]

Where:

\( \Delta T_f \) — Depression in Freezing Point (Kelvin)
\( P_o^A \) — Vapour Pressure of Pure Solvent (Pascal)
\( P_A \) — Vapour Pressure of Solvent in Solution (Pascal)
\( [R] \) — Universal gas constant (8.314 J/mol·K)
\( T_{fp} \) — Solvent Freezing Point (Kelvin)
\( \Delta H_{fusion} \) — Molar Enthalpy of Fusion (J/mol)

Explanation: The formula relates the change in vapour pressure to the freezing point depression through thermodynamic principles.

3. Importance of Freezing Point Depression

Details: Understanding freezing point depression is crucial in chemistry, biology, and engineering applications like antifreeze solutions and food preservation.

4. Using the Calculator

Tips: Enter all required values in their respective units. Ensure the vapour pressure of solution is less than or equal to the pure solvent's vapour pressure.

5. Frequently Asked Questions (FAQ)

Q1: What is the physical meaning of freezing point depression?
A: It describes how adding solute particles disrupts the solvent's ability to form a solid lattice, requiring lower temperatures to freeze.

Q2: Why does vapour pressure affect freezing point?
A: Freezing point and vapour pressure are both colligative properties that depend on the concentration of solute particles in solution.

Q3: What are typical values for molar enthalpy of fusion?
A: For water it's 6.01 kJ/mol, but varies by substance. Always use values appropriate for your specific solvent.

Q4: Can this calculator be used for any solvent?
A: Yes, as long as you have accurate input values for that particular solvent.

Q5: How accurate is this calculation?
A: It provides theoretical values assuming ideal behavior. Real-world systems may show slight deviations.