Equilibrium Processes in Physical Chemistry

What condition is necessary to achieve solid-liquid equilibrium in a thermos flask?

In the liquid-vapour equilibrium setup, what happens to the volume of water on the watch glass over time?

What does the rise in mercury level in the manometer signify during liquid-vapour equilibrium?

Which of the following statements about phase transformations is true?

What is the primary factor causing the pressure increase in the liquid-vapour equilibrium setup?

Equilibrium Processes in Physical Processes

Equilibrium is best understood by examining physical processes.
Phase transformations like solid-liquid and liquid-gas transitions are common examples of equilibrium processes.

Solid-Liquid Equilibrium

A system of ice and water at 273 K, in a perfectly insulated container, demonstrates equilibrium.
The rates of transfer of molecules between the solid and liquid state are equal, resulting in constant mass of ice and water.

Liquid-Vapour Equilibrium

This equilibrium can be observed by placing a watch glass with water inside a sealed box containing a desiccant (e.g. anhydrous calcium chloride/phosphorus pentoxide) and a U-tube manometer.
As water evaporates inside the sealed box, the mercury level in the manometer limb will rise due to the increase in pressure from water vapor.
When the mercury level reaches a constant value, equilibrium is achieved.
Initially, the box has little to no water vapor, and the pressure increase is primarily due to the addition of water vapor.
As water vapor increases, the rate of evaporation decreases, eventually balancing the rate of condensation. This balance marks the point of equilibrium.

This quiz explores the concept of equilibrium in physical processes, focusing on solid-liquid and liquid-vapor equilibria. It examines how phase transformations occur and emphasizes the conditions under which equilibrium is established in closed systems. Test your understanding of these fundamental concepts in physical chemistry.