Question

High in the mountains, an explorer notes that the water for tea is boiling vigorously at a temperature of 80 °C. Use the data in the table below to estimate the atmospheric pressure at the altitude of the camp. Estimate AHva for water between 80 and 82 °C. Atmospheric pressure - atm ΔΗ kJ/mol vap Vapor Pressure of Water at Various Temperatures P atm 0.413 0.431 0.449 0.467 0.486 0.506 0.527 0.548 0.571 0.593 0.617 0.641 0.666 0.692 0.719 0.746 0.774 0.804 0.834 0.865 78 79 80 81 82 83 84 85 86 87 89 90 91 92 93 94 95 96

Answer 1

Water boils at 80 deg C. This happens when vapour pressure of water is equal to atmospheric pressure.

Hence, atmospheric pressure at the altitude of camp is equal to vapour pressure of water at 80 deg C which is 0.467 atm.

According to clausius clapeyron equation,

Substitute values for 80 deg C and 82 deg C

Convert unit from J to kJ