Specific Latent Heat Formula:
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Definition: This calculator estimates the specific latent heat of vaporization using Trouton's rule, which relates the boiling point and molecular weight of a substance.
Purpose: It helps chemists and engineers quickly estimate the energy required for phase changes without detailed experimental data.
The calculator uses the formula:
Where:
Explanation: Trouton's rule states that the entropy of vaporization is approximately constant for many liquids at their boiling points.
Details: Knowing the specific latent heat is crucial for designing distillation systems, refrigeration cycles, and other phase-change processes.
Tips: Enter the boiling point in Kelvin and molecular weight in kg. Both values must be > 0.
Q1: What is Trouton's rule?
A: It's an empirical rule stating that the entropy of vaporization is approximately 10.5 times the universal gas constant for many liquids.
Q2: How accurate is this calculation?
A: It provides a reasonable estimate (within 10-20%) for many non-polar liquids but may be less accurate for polar or associating liquids.
Q3: What units should I use for molecular weight?
A: The calculator expects kg (SI units), but you can use g/mol if you multiply the result by 1000.
Q4: Can I use this for any substance?
A: It works best for non-polar liquids with boiling points between 100-1000K. It's less accurate for water, alcohols, or other associating liquids.
Q5: Why is the universal gas constant included?
A: It converts the entropy term (10.5[R]) into energy units, making the result dimensionally consistent.