Chapter 9, Problem 20TE

Water vapor changes phase when it changes into snow. Does this change of phase tend to warm or to cool the surrounding air?

To determine

Whether the change of phase from water vapor to snow tends to change the surrounding air.

Answer to Problem 20TE

The change of phase from water vapor to snow tends to make the surrounding air cooler due to energy transfer.

Explanation of Solution

When the phase of a substance changes to another phase, a transfer of thermal energy occurs. Whenever a substance changes phase, energy is either given to the substance or taken from it.

When there is a change from water vapor to snow, energy is taken from the vapor. The heat is transferred to air from the vapor. And thus,s the surrounding air gets cooler when there is a phase change from vapor to snow

Conclusion:

Therefore, the change of phase from water vapor to snow tends to make the surrounding air cooler due to energy transfer.