Which graph best describes how the vapor pressure of a substance varies with temperature according to the Clausius-Clapeyron equation? ln(P) is plotted on the y-axis, and 1/T is plotted on the x-axis. The origin (0, 0) is not necessarily located where the axes cross.
A)I
B)II
C)III
D)IV

Question

Which graph best describes how the vapor pressure of a substance varies with temperature according to the Clausius-Clapeyron equation? ln(P) is plotted on the y-axis, and 1/T is plotted on the x-axis. The origin (0, 0) is not necessarily located where the axes cross.  
A)I 
B)II 
C)III 
D)IV

Quizplus · Accepted Answer

According to the Clausius-Clapeyron equation, the natural log of vapor pressure and the inverse of absolute temperature have a linear relationship. Therefore, when ln(P) is plotted on the y-axis and 1/T is plotted on the x-axis, the graph should be a straight line. Choice B is the only graph that depicts a straight line passing through the origin, as expected from the equation.

Which Graph Best Describes How the Vapor Pressure of a Substance