If we place some liquid in a container in which none of its molecules is in the vapour phase, evaporation will occur as vapour particles escape from the surface. In an open system, the vapour particles will leave so the liquid will continue to evaporate and equilibrium will not be reached. In this situation, the liquid will eventually all be converted into vapour - this is what happens, for example, when a puddle of water dries up or clothes are hung up to dry outside.
Temperature
The kinetic theory of matter gives us a model to describe the behaviour of liquids and gases. As temperature increases, there will be more vapour particles due to the increase rate of evaporation. Thus vapour pressure increases,
17.1.2 Sketch graphs showing the relationship between vapour pressure and temperature and explain them in terms of kinetic theory
17.1.3 State and explain the relationship between enthalpy of vapourization, boiling point and intermolecular forces
Stronger intermolecular forces
Higher enthalpy of vapourization
Lower vapour pressure
Higher boiling point
Weaker intermolecular forcese
Lower enthalpy of vapourization
Higher vapour pressure
Lower boiling point
The vapour pressure of a substance depends on its temperature and on the strength of the intermolecular forces present. The higher the temperature and the weaker the intermolecular forces, the higher the vapour pressure.
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