Sulfur dioxide has a vapor pressure of 462.7 mm Hg at -21.0 °C and a vapor pressure of 140.5 mm Hg at -44.0 °C.What is the enthalpy of vaporization of sulfur dioxide? (R = 8.314 J/K⋅mol)

Question

Quizplus · Accepted Answer

We can use the Clausius-Clapeyron Equation:

ln(P₂/P₁) = -(ΔHvap/R) * (1/T₂ - 1/T₁)

where P₁ and P₂ are the vapor pressures at temperatures T₁ and T₂ respectively.

Rearranging and plugging in the values, we get:

ΔHvap = -(R * ln(P₂/P₁)) / (1/T₂ - 1/T₁)

ΔHvap = -((8.314 J/K⋅mol) * ln(140.5/462.7 mm Hg)) / (1/(-44.0 + 273.15) K - 1/(-21.0 + 273.15) K)

ΔHvap = 24.9 kJ/mol

Therefore, the enthalpy of vaporization of sulfur dioxide is 24.9 kJ/mol, which is closest to choice D.

Sulfur Dioxide Has a Vapor Pressure of 462