Why does the temperature of a substance increase as vapor pressure increases?

1 Answer
Dec 6, 2015

Vapour pressure is defined as the pressure exerted by the gas molecules on the surface of the liquid it is in equilibrium with at a particular temperature.

The physical meaning is this: the liquid molecules at the surface leave the liquid phase and enter the gas phase and vice-versa as long as an equilibrium is maintained.

When the temperature of the liquid is increased more liquid molecules at the surface will try to escape to the gas phase(because of higher kinetic energy of those molecules) which causes the number of molecules in the gas phase to increase and hence from the definition the vapour pressure also increases.