Chapter U5.3, Problem 5E

Interpretation Introduction

Interpretation:

The term evaporation and reason for it to be known as a cooling process needs to be explained.

Concept Introduction :

The condition in whichtwo substances in physical contact with each other exchange no heat energy, is known as thermal equilibrium.

Answer to Problem 5E

When a substance absorbs energy during change in liquid phase to gaseous phase, energy is transferred from surroundings to the system and the surroundings become cold.

Explanation of Solution

The process of change of a liquid substance to gas is known as evaporation. A liquid can be changed into a gas, if sufficient amount of energy gained by the liquid in the form of heat. The energy required for the change is called the heat of evaporation.

For example: The human body makes use of the evaporation process while sweating.

When a substance absorbs energy during change in liquid phase to gaseous phase, energy is transferred from surroundings to the system and the surroundings become cold.