Pressure of water vapour is given by

Question

RRB Paper · Accepted Answer

The vapor pressure of water is the pressure at which water vapor is in thermodynamic equilibrium with its condensed state.

Pressure of water vapour is given by

ln(P1/P2) = (ΔHvap/R)((1/T2) - (1/T1))

where

ΔHvap: The enthalpy of vaporization of the liquid.

• R: The real gas content, or 8.314 J/(K × Mol).

• T1: The temperature at which the vapor pressure is known (or the starting temperature.)

• T2: The temperature at which the vapor pressure is to be found (or the final temperature.)

• P1 and P2: The vapor pressures at the temperatures T1 and T2, respectively.

ln(P1/P2) = (?Hvap/R)((1/T2) - (1/T1)).