Chapter 12.4, Problem 27SSC

Interpretation Introduction

Interpretation:

The change in phase due to addition or removal of energy must be explained.

Concept introduction:

Phase change is a process in which the physical state of a substance is changed.

Answer to Problem 27SSC

Addition of thermal energy decreases the intermolecular force and thus helps in phase change. Removal of thermal energy increases the intermolecular force and thus helps in phase change.

Explanation of Solution

Solid is converted to liquid when it is heated at melting temperature. The liquid is converted to vapor when it is heated at boiling temperature.

For example ice is melted to liquid water when heat is provided. Liquid water is converted to water vapor when it is heated. When water vapor is cooled then it is condensed to liquid water. When liquid water is cooled further it is converted to ice.

Conclusion

Addition or removal of energy can cause phase change.