Practice question · Numerical answer
A substance has a latent heat of vaporisation of 40 kJ/mol and boils at 350 K. Compute its entropy of vaporisation in J/mol/K, to the nearest whole number.
Hints
- At the transition the two phases are in equilibrium, so the entropy change is the latent heat over the temperature.
- Compute 40000 / 350.
Show the answer
114 (answers within ±2 count)
Why
J/mol/K. Most liquids cluster near 88 (Trouton’s rule); a markedly higher value signals strong association in the liquid, such as hydrogen bonding.
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