Chapter 15, Problem 15.74P

Interpretation Introduction

Interpretation:

The number of triple points in phase diagram of sulfur and the process that occurs when sulfur is heated from $40°\text{C}$ to $200°\text{C}$ at $1\text{atm}$ has to be reported. The pressure below which sublimation occurs has to be also reported.

Concept Introduction:

A plot of pressure against temperature that displays the stable range of a particular phase is known as phase diagram.

The phase diagram has three regions. Each region represents a particular stable phase like solid, liquid, or gas separated by boundary lines. Boundaries represent the equilibrium between two phases. The points of intersection at which the three boundary lines intersect is known as triple point. At triple point, all three phases exist in equilibrium.

The vapor pressure at equilibrium for liquid increases as the temperature goes up to critical point where the vapor pressure curve terminates abruptly. The gas and the liquid phases become inseparable above critical temperature.