Question

Assume that you have a liquid in a cylinder equipped with a movable piston. There is no air in the cylinder, the volume of space above the liquid is 200 mL, and the equilibrium vapor pressure above the liquid is 29.0 mm Hg: What is the equilibrium pressure above the liquid when the volume of space is decreased from 200 mL to 100 mL at constant temperature? P = _______________ mm Hg Express your answer to two significant figures.

Answer 1

Solution :-

The vapor pressure of the liquid is the pressure exerted by the vapor which are in equilibrium with the liquid.

At the constant temperature the vapor pressure of the liquid remains same irrespective of the amount of the liquid and volume of the container because the vapor pressure only changes with temperature.

So even when the volume is decreased from 200 ml to 100 ml the vapor pressure will remain the same

so the vapor pressure at 100 ml volume will be 29 mmHg