Blundell Thermal Physics · Problem 28.5

Phase transitions

Physics — Statistical Mechanics · vapour-pressure-latent-heat-determination

Problem

The equilibrium vapour pressure

p

of water as a function of temperature is given in the following table: [table — see PDF] Deduce a value for the latent heat of evaporation

L_v

of water. State clearly any simplifying assumptions that you make. Estimate the pressure at which ice and water are in equilibrium at

-2^\circ

C, given that ice cubes float with

4/5

of their volume submerged in water at the triple point (

0.01^\circ

612

Pa).

[

Latent heat of sublimation of ice at the triple point,

L_s = 2776 \times 10^3

J kg

^{-1}

]