Surface Tension Formula:
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Definition: This calculator estimates the surface tension of a fluid based on critical temperature, current temperature, and molar volume using the Eötvös rule.
Purpose: It helps researchers and engineers determine the surface tension of liquids which is important in fluid mechanics, material science, and chemical engineering applications.
The calculator uses the formula:
Where:
Explanation: The formula relates surface tension to the temperature difference from critical point and molar volume, accounting for molecular interactions.
Details: Surface tension affects capillary action, droplet formation, wetting phenomena, and is crucial in processes like coating, printing, and biological systems.
Tips: Enter the critical temperature, current temperature (both in Kelvin), and molar volume (in m³/mol). All values must be positive.
Q1: What is the Eötvös constant?
A: It's a physical constant (2.1×10⁻⁷ N·m/K·mol²/³) that relates surface tension to temperature and molar volume in the Eötvös rule.
Q2: How accurate is this calculation?
A: It provides reasonable estimates for simple liquids near their boiling points but may be less accurate for complex molecules or near critical points.
Q3: Where can I find critical temperature values?
A: Critical temperatures are tabulated in chemical engineering handbooks or material safety data sheets for common substances.
Q4: What are typical surface tension values?
A: Water at 20°C has γ≈72 mN/m, while organic solvents typically range from 20-50 mN/m at room temperature.
Q5: Does this work for mixtures?
A: The simple Eötvös rule is best for pure substances. Mixtures require more complex models accounting for composition.