Water boils at 373 K. The molar enthalpy of vaporization for water is 40.7 kJ/mol. If one mole of water is at 373 K when it starts to boil, its temperature when it all has boiled will be ____________________. a. 273 K c. 373 K b. 343 K d. 413 K
When water is boiling liquid is passing to vapor phase and all the heat is used by the molecules to gain the necessary energy to make the change; so during this change of phase the temperature of the water does not increase. That is why the temperature remains constant during the change of phase.