explain vapour pressure

Asked by shuchi.saumya | 5th Oct, 2010, 12:00: AM

Expert Answer:

Dear student
The pressure exerted by a vapor in equilibrium with its solid or liquid phase is called vapour pressure.

Suppose we have a closed container into which we pour some water. As soon as we add the water we check a pressure gauge connected to the container. We let the container sit for a while and then we check the pressure again.

As the water evaporates the pressure exerted by the vapor above the liquid increases, until at some point, the pressure reaches a constant value which is called the vapor pressure of the substance

Vapor pressure increases with temperature

  • At higher temperature more molecules have the necessary kinetic energy to escape the attractive forces of the liquid phase
  • The more molecules in the vapor phase, the higher the vapor pressure
 The temperature at which vapour pressure becomes equal to atmospheric pressure is called boiling point
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Answered by  | 5th Oct, 2010, 01:14: PM

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