At 21C the vapor pressure of water is 00277 atm Calculate KP

At 21°C, the vapor pressure of water is 0.0277 atm. Calculate KP and Kc for the process: H2O(l) H2O(g)

Solution

The K_p expression involved only gases , so the K_p = 0.0277

K_p and K_c are related as follows:

K_p = K_c (RT)ⁿ {Where n = 1-0 = 1}

0.0277 = K_c (0.0821 * 294)

K_c = 1.147 x 10^-3