Work of Cohesion given Surface Tension Calculator

Work of Cohesion Formula:

\[ W_{Coh} = 2 \times \gamma \times [Avaga-no]^{1/3} \times (V_m)^{2/3} \]

Work of Cohesion (J/m²):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Work of Cohesion?

Definition: Work of Cohesion is defined as the surface free energy increased by separating a column of pure liquid into two halves.

Purpose: It quantifies the energy required to overcome intermolecular forces at a liquid's surface.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ W_{Coh} = 2 \times \gamma \times [Avaga-no]^{1/3} \times (V_m)^{2/3} \]

Where:

\( W_{Coh} \) — Work of Cohesion (J/m²)
\( \gamma \) — Surface Tension of Fluid (N/m)
\( [Avaga-no] \) — Avogadro's number (6.02214076×10²³ mol⁻¹)
\( V_m \) — Molar Volume (m³/mol)

Explanation: The formula relates surface tension to the energy required to separate liquid molecules, accounting for molecular density via Avogadro's number and molar volume.

3. Importance of Work of Cohesion

Details: Understanding work of cohesion helps in studying liquid properties, surface phenomena, and designing processes like coating, wetting, and adhesion.

4. Using the Calculator

Tips: Enter the surface tension (default 0.073 N/m for water at 20°C) and molar volume (default 22.4×10⁻⁶ m³/mol for ideal gases at STP). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What are typical surface tension values?
A: Water at 20°C has 0.073 N/m, mercury 0.485 N/m, and ethanol 0.022 N/m.

Q2: Why is Avogadro's number used in this formula?
A: It relates macroscopic measurements to molecular-scale interactions.

Q3: How does temperature affect work of cohesion?
A: Generally decreases with temperature as intermolecular forces weaken.

Q4: Can this be used for mixtures?
A: No, this formula applies only to pure substances.

Q5: What's the relationship to surface energy?
A: Work of cohesion equals twice the surface energy for a liquid.