Chapter 14.1, Problem 4R

To determine

The behavior of the particles of the substance at its boiling point.

Explanation of Solution

Introduction:

The particles of the substance need energy for the movement. The motion of the particles of substance depends on the energy available for particles.

The particles of the substance in the solid-state remain fixed but start moving if some energy provided to the particle. The molecular attraction force between the particles in a solid-state is greater than the liquid state. When some energy gives to solid, the solid starts to melt and particles of the substance started moving.

If the temperature of the liquid substance further increases, then the movement of the particle become faster. The energy for the particles at the boiling point of the substance becomes higher. The particles started moving faster at the boiling point than at the melting point because the molecular force between particles becomes negligible at the boiling point.

Conclusion:

Thus, the particles of the substance move freely at the melting point of the substance.