Given that the density of liquid water is 0958 gmL and the d

Given that the density of liquid water is 0.958 g/mL and the density of water vapor is 0.5983 g/L at the normal boiling point, compute the boiling point of water (in K) on a mountain top where the pressure is 0.75 atm.
Hint: Use the form of Clausius Clapeyron where you leave the pressure dependence on T in the ln form.
Hint: Remember it takes longer to cook food on mountains.

Solution

Normal boiling point of water = 100 oC = 373 K

pressure P2 = 1 atm

at mountain top :

pressure P1 = 0.75 atm

delta Hvap = 40.65 kJ / mol

ln (p2 / p1) = deltaHvap / R [1/ T1 - 1/T2]

ln (1 / 0.75) = 40.65 / 8.314 x 10^-3 [1 / T1 - 1/ 373]

T1 = 365 K

boiling point of water on mountain top = 365 K or 92 oC