Question

How can the pressure of water vapor be increased in the following equilibrium? How can I solve it?

H₂O (l) ⇌ H₂O (g) ΔH = 41 kJ

Answer 1

Increasing the temperature or decreasing the pressure over the liquid water can increase the pressure of water vapor in the equilibrium between liquid and gaseous water.

Step-by-step explanation:

The pressure of water vapor in the equilibrium H₂O(l) ⇌ H₂O(g) with ΔH = 41 kJ can be increased by applying Le Chatelier's principle. To favor the production of more gaseous water, we could:

1. Increase the temperature, as the reaction is endothermic (absorbs heat).
2. Decrease the pressure over the liquid water, which shifts the equilibrium towards producing more gas to increase the pressure.

Remember that adding more liquid water will not change the vapor pressure, because the system will still reach the same equilibrium vapor pressure at a given temperature.