Chapter 17.3, Problem 29LC

Interpretation Introduction

Interpretation: The molar heat of fusion is to be compared to the molar heat of solidification.

Concept Introduction : Molar heat of fusion is the amount of energy needed to change one mole of a substance from the solid phase to the liquid phase at constant temperature and pressure.

Molar heat of solidification is the amount of energy released to change one mole of a substance from the liquid phase to the solid phase at constant temperature and pressure.

Answer to Problem 29LC

The molar heat of fusion has the same specific value as the molar heat of solidification, but their signs are opposite.

Explanation of Solution

The energy consumed during fusion to break the intermolecular bonds is released back during solidification to form the intermolecular forces since fusion and solidification of a given substance are absolute reverse processes.