Question

A) 9.80g of water vapor condenses on a soda can at 100.0°C? Given : latent heat of vaporization 2260 J/g latent heat of fusion 334 J/g (i) State the phase change for the above process (ii) Calculate the amount of energy transfer

Answer 1

A-i: The water is changing from a gaseous phase to a liquid phase.

A-ii: The energy transferred is -22.4 kJ.

Explanation:

For answer A-i, as the water condenses, it is changing from a gaseous phase to a liquid phase.

For answer A-ii:

Since the phase change is the reverse of vaporization, the latent heat of vaporization must be changed to a latent heat of condensation by reversing its sign (heat is released during the phase change):

`9.90 cancel(g) * (-2260 J)/cancel(g) = -22374 J ~= -22.4 kJ`

SEE: https://en.wikipedia.org/wiki/Enthalpy_of_vaporization