The mean atmospheric pressure at the surface of Mars is about

PHYSICS · Subjective · Fermi University Physics · Thermal, Statistical & Complex Systems · Interacting systems, real gases and phase equilibria · Interacting systems, real gases and phase equilibria

Thermal Physics, Ch Phase coexistence and the Clausius-Clapeyron relation

Problem

The mean atmospheric pressure at the surface of Mars is about 610 Pa610\,\mathrm{Pa}. Water boils at 373.15 K373.15\,\mathrm{K} under 101.3 kPa101.3\,\mathrm{kPa}, and its latent heat of vaporisation may be taken as constant at L=40.7 kJ mol−1L = 40.7\,\mathrm{kJ\,mol^{-1}} over the range needed. Treat the vapour as an ideal gas and neglect the molar volume of the liquid beside that of the vapour. Estimate, to the nearest kelvin, the temperature at which liquid water would boil at the mean Martian surface pressure. Then compare that pressure with water's triple point, 273.16 K273.16\,\mathrm{K} and 612 Pa612\,\mathrm{Pa}: does liquid water have a stable boiling point there at all? (R=8.314 J mol−1 K−1R = 8.314\,\mathrm{J\,mol^{-1}\,K^{-1}}.)

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