Vapor pressure is the pressure exerted by the gas molecules in a closed container when a substance is in its liquid or solid state. It is a measure of how easily a substance can evaporate into a gas.
Vapor pressure increases with an increase in temperature. This is because as temperature rises, the kinetic energy of molecules increases, causing them to escape from the liquid or solid phase and enter the gas phase, increasing the pressure.
The intermolecular forces between solvent molecules determine the strength of the bonds that hold them together. Stronger intermolecular forces result in lower vapor pressure, as more energy is required to break the bonds and allow molecules to escape into the gas phase.
Vapor pressure and boiling point are inversely related. A substance with a high vapor pressure will have a lower boiling point, as the molecules are more easily able to escape into the gas phase at lower temperatures.
Vapor pressure can be measured using several methods, including the manometer method, the boiling point method, and the isopiestic method. These methods involve creating a closed system with the liquid or solid substance and measuring the pressure exerted by the gas phase at different temperatures.