Final answer:
The student's question relates to the Clausius-Clapeyron equation, which describes the relationship between vapor pressure and temperature. By plotting the natural logarithm of vapor pressure against the inverse of temperature, one can obtain a line with a negative slope that helps calculate the enthalpy of vaporization of a substance.
Step-by-step explanation:
Understanding Vapor Pressure and Clausius-Clapeyron Equation
The question involves understanding the concept of vapor pressure and its relationship with temperature. The Clausius-Clapeyron equation is a key component in analyzing this relationship. The equation provides a way to understand how the vapor pressure of a substance changes with temperature, indicating that as the temperature of a substance increases, its vapor pressure also rises. This relationship is depicted graphically by plotting the natural logarithm of vapor pressure against the inverse of temperature, resulting in a linear plot with a slope of −∏ΔHvap/R, where ∏ΔHvap is the enthalpy of vaporization and R is the universal gas constant.
When measuring the vapor pressure of an unknown substance at several temperatures, the linear plot obtained allows us to calculate the enthalpy of vaporization (∏ΔHvap) of the liquid. Since the slope is provided, it is possible to discern the value of ∏ΔHvap by using the slope and the known value of R, revealing important thermodynamic properties of the substance. The concept of normal boiling point is also closely related, as it is the temperature at which a liquid's vapor pressure equals 1 atm. This point changes with alterations in surrounding pressure, influencing phenomena such as cooking at various elevations.