Which statement about how the vapor pressure (P) of a liquid depends on temperature is correct? A)The larger the enthalpy of vaporization, the smaller the change in vapor pressure for a given change in temperature. B)A graph of P versus 1/T is linear with a slope $\Delta$H_vap/R. C)The smaller the intermolecular interactions, the greater the change in vapor pressure for a given change in temperature. D)A graph of ln(P) versus T is linear with a slope $\Delta$H_vap/R. E)A graph of ln(P) versus 1/T is linear with a slope $\Delta$H_vap/R.

Question

Quizplus · Accepted Answer

The vapor pressure of a liquid is given by the Clausius-Clapeyron equation: ln(P2/P1) = (-ΔHvap/R)(1/T2 - 1/T1), where P1 and T1 are initial pressure and temperature, P2 and T2 are final pressure and temperature, ΔHvap is the enthalpy of vaporization, and R is the gas constant. Rearranging this equation gives ln(P) = (-ΔHvap/R)(1/T) + C, where C is a constant. This equation shows that a plot of ln(P) versus 1/T should be linear with a slope of -ΔHvap/R, regardless of the intermolecular interactions or the magnitude of the change in vapor pressure with temperature. Therefore, choice E is the correct answer.

Which Statement About How the Vapor Pressure (P) of a Liquid