Surface Tension Formula:
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Definition: This calculator estimates the surface tension of a fluid based on the Eötvös rule, using critical temperature, current temperature, molecular weight, and liquid density.
Purpose: It helps researchers and engineers determine the surface tension of liquids when molecular properties are known.
The calculator uses the Eötvös formula:
Where:
Explanation: The formula relates surface tension to the temperature difference from critical point and the molar volume of the liquid.
Details: Surface tension affects capillary action, wetting, detergency, and is crucial in many industrial processes and biological systems.
Tips: Enter the critical temperature, current temperature (both in Kelvin), molecular weight in kg, and liquid density in kg/m³. All values must be > 0.
Q1: What is the Eötvös constant?
A: It's an empirical constant (2.1 × 10⁻⁷ J/K·mol²/³) that appears in the Eötvös rule for surface tension.
Q2: How accurate is this calculation?
A: The Eötvös rule gives approximate values and works best for simple, non-associated liquids.
Q3: Where can I find critical temperature values?
A: Critical temperatures are tabulated in chemical data handbooks for many substances.
Q4: Why is there a -6 in the formula?
A: This is an empirical correction factor in the Eötvös equation to improve accuracy.
Q5: What are typical surface tension values?
A: Water at 20°C has γ ≈ 0.0728 N/m, while organic liquids typically range from 0.02 to 0.05 N/m.