Banner

The Vapor Pressure of Acetone

The mercury on both sides of the manometer is at the same height because the pressure on both sides is equal.
Vapor pressure of acetone fig. 1
The flask is capped carefully so that the pressure on both sides remains equal.
Vapor pressure of acetone fig.2
As a little acetone is injected into the sealed flask the pressure in the flask begins to increase as the acetone evaporates.
Vapor pressure of acetone fig 3
The 300 torr increase in pressure is due to the evaporation of the liquid in the flask. The vapor pressure of the liquid is equal to the increase in pressure after the pressure stops changing.

Because the amount of liquid and vapor have stopped changing, we say the liquid and vapor are in equilibrium at this point.

Vapor pressure of acetone fig. 4

*Return to Vapor Pressure

Logo