Vapor Pressure

[Simon Dionson 4I]

What is the relationship between the strength of intermolecular forces and vapor pressure?

[Alan Wu]

Vapor pressure is a measure of the pressure exerted by a gas above a liquid in a sealed container. Strong intermolecular forces produce a lower rate of evaporation and a lower vapor pressure. Weak intermolecular forces produce a higher rate of evaporation and a higher vapor pressure.

[Ryan Chang 1C]

Vapor pressure is correctly defined in the post above. Knowing what vapor pressure is can help you solve problems like 3F.19 part (b) Explain why the vapor pressure of diethyl ether (C2H5OC2H5) is greater than that of water.

Since water has hydrogen bonds and C2H5OC2H5 does not, the molecules are held together tighter in water, thus giving water a lower vapor pressure.