Home Back

Cryoscopic Constant given Depression in Freezing Point Calculator

Cryoscopic Constant Formula:

\[ k_f = \frac{\Delta T_f}{i \times m} \]

K
mol/kg

Unit Converter ▲

Unit Converter ▼

From: To:

1. What is Cryoscopic Constant?

Definition: The Cryoscopic Constant (kf) is the freezing point depression when a mole of non-volatile solute is dissolved in one kg of solvent.

Purpose: It helps determine how much a solute will depress the freezing point of a solvent, which is important in chemistry and material science.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ k_f = \frac{\Delta T_f}{i \times m} \]

Where:

Explanation: The freezing point depression is divided by the product of the Van't Hoff factor and molality to determine the cryoscopic constant.

3. Importance of Cryoscopic Constant

Details: This constant is crucial for determining molecular weights of solutes, studying solution properties, and in various industrial applications like antifreeze formulations.

4. Using the Calculator

Tips: Enter the freezing point depression (ΔTf) in Kelvin, Van't Hoff factor (default 1.008), and molality in mol/kg (default 1.79). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the Van't Hoff factor?
A: It's a measure of the effect of solute particles on colligative properties. For non-electrolytes, it's typically 1.

Q2: What are typical values for cryoscopic constants?
A: For water it's 1.86 K·kg/mol, benzene 5.12 K·kg/mol, and acetic acid 3.90 K·kg/mol.

Q3: Why is molality used instead of molarity?
A: Molality is temperature-independent (based on mass), while molarity (based on volume) changes with temperature.

Q4: What affects the cryoscopic constant?
A: It's solvent-specific and depends on the solvent's molar mass and enthalpy of fusion.

Q5: How accurate is this calculation?
A: It's accurate for ideal solutions. For real solutions, activity coefficients may be needed.

Cryoscopic Constant Calculator© - All Rights Reserved 2025