The vapor pressure of liquid water at 58.0˚C and 73.0˚C is 136.1 and 265.7 torr respectively. The vapor pressure of liquid water at 69.0˚C is _____ torr.

Question

Quizplus · Accepted Answer

We can use the Clausius-Clapeyron equation to solve this problem:
ln(P₂/P₁) = -ΔHvap/R * (1/T₂ - 1/T₁)
Where P₁ and T₁ are the vapor pressure and temperature at 58.0 ˚C, P₂ and T₂ are the vapor pressure and temperature at 73.0 ˚C, R is the gas constant, and ΔHvap is the enthalpy of vaporization of water.
Solving for ΔHvap and substituting the values given, we get:
ΔHvap = -((ln(265.7/136.1))/(1/331.15-1/331.15)) * 8.314 = 41.0 kJ/mol
Now, we can use the same equation to solve for P₃, the vapor pressure of water at 69.0˚C:
ln(P₃/136.1) = -41000/8.314 * (1/342.15 - 1/331.15)
Solving for P₃, we get:
P₃ = 222.6 torr
Therefore, the answer is choice C, 223 torr.

The Vapor Pressure of Liquid Water at 58