Molar heat of vaporization of water is_________________?
Correct answer: A. 40.7 KJ/mole
- A. 40.7 KJ/mole
- B. 40.7 J/mole
- C. 40.7 cal/mole
- D. 40.7 Kcal/mole
Explanation
The molar heat of vaporization of water is the heat required to convert 1 mole of liquid water into vapour at its boiling point, and its accepted value is about 40.7 kJ/mol. Students may choose 40.7 J/mol by missing the factor of 1000 between joules and kilojoules.
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About Evaporation, Boiling Point and Vapour Pressure
Evaporation is the escape of higher-energy molecules from a liquid surface, while vapour pressure is the pressure exerted by vapour in equilibrium with that liquid. The topic distinguishes evaporation from boiling and relates both to temperature, intermolecular forces, surface area, atmospheric pressure and the boiling point.
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