What does the Clausius-Clapeyron equation utilize to express the relationship between vapour pressure and temperature?

The Clausius-Clapeyron equation describes the relationship between the vapor pressure of a substance and its temperature, specifically for phase transitions such as vaporization. The correct expression involves the enthalpy of vaporization (Δ_vapH) divided by the product of the ideal gas constant (R) and the temperature squared (T²).

This relationship highlights how changes in temperature affect vapor pressure, showcasing that with an increase in temperature, the vapor pressure of a liquid generally increases. The Δ_vapH represents the heat required to vaporize a unit amount of the substance, which directly influences the vapor pressure as temperature changes.

By understanding this relationship, one can derive meaningful insights about the behavior of substances in different phases under varying conditions. The significance of Δ_vapH in the equation aligns with the thermodynamic principles governing phase changes, making it a fundamental concept in physical chemistry. This equation is particularly useful in calculating the vapor pressures at different temperatures and in studying systems in equilibrium.

The other options, while they may represent important thermodynamic relationships, do not directly describe the connection between vapor pressure and temperature as effectively as the format presented in the correct answer focuses on the enthalpy of vaporization, encapsulating the energetic aspect of