The normal freezing point of n-octane (C₈H₁₈) is -57 °C. (d) Is there any temperature at which liquid n-octane and solid n-octane are in equilibrium? Explain.

Key Concepts

Phase Equilibrium

Phase equilibrium occurs when two phases of a substance, such as solid and liquid, coexist at a specific temperature and pressure. At this point, the rates of melting and freezing are equal, leading to a stable condition where both phases are present. For n-octane, this equilibrium can be established at its freezing point, where the solid and liquid forms can exist together.

Freezing Point

The freezing point is the temperature at which a liquid turns into a solid under a given pressure. For n-octane, the normal freezing point is -57 °C, meaning that at this temperature, n-octane can exist as both a liquid and a solid. Understanding this concept is crucial for determining the conditions under which n-octane can transition between its phases.

Thermodynamic Stability

Thermodynamic stability refers to the state of a system where it is at its lowest energy configuration, making it resistant to change. In the context of n-octane, the equilibrium between its solid and liquid phases represents a stable state at the freezing point. Any deviation from this temperature will favor either the solid or liquid phase, illustrating the importance of temperature in phase behavior.