Vapor Pressure and Atmospheric Pressure

In summary, the vapor pressure of a liquid is temperature dependent and not affected by atmospheric pressure. This means that even if the pressure inside a sealed container is increased, it will not have a significant impact on the evaporation rate of a highly volatile liquid. This is because the gas in the container is mainly empty space and the equilibrium of the liquid's evaporation and condensation is determined by the partial pressure of the molecules, not the total pressure.
  • #1
chingkui
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From what I have read so far, the vapor pressure of a liquid is temperature dependent while it is independent of the atmospheric pressure. I am not sure why atmospheric pressure would have no effect of the vapor pressure though. For example, if a highly volatile liquid is placed in a sealed container, and I increase the pressure inside the container to an extremely high value, wouldn't the high pressure make it harder for the volatile liquid to evaporate?
 
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  • #2
Gas is mainly empty space (unless you have a really high pressure), so the evaporation rate is nearly independent of the pressure. The condensation rate depends on the partial pressure of those molecules, therefore the equilibrium depends on the partial pressure and not the total pressure.
 

FAQ: Vapor Pressure and Atmospheric Pressure

What is vapor pressure?

Vapor pressure is the pressure exerted by the gaseous form of a substance in equilibrium with its liquid or solid form at a given temperature.

How does vapor pressure relate to atmospheric pressure?

Vapor pressure is affected by atmospheric pressure, as the pressure of the surrounding air can impact the rate at which a substance evaporates. When atmospheric pressure is lower, vapor pressure will be higher, leading to a faster evaporation rate.

What factors affect vapor pressure?

The main factors that affect vapor pressure are temperature, intermolecular forces, and the characteristics of the substance itself, such as its molecular weight and polarity.

How is vapor pressure measured?

Vapor pressure can be measured using various techniques, such as the boiling point method, the static method, the dynamic method, and the isopiestic method. These methods involve measuring the pressure and temperature of a sample of the substance and using mathematical equations to calculate the vapor pressure.

What is the significance of vapor pressure in everyday life?

Vapor pressure plays a crucial role in many everyday processes, such as cooking, distillation, and the functioning of engines. It also affects the weather and climate, as it is related to the rate of evaporation and condensation of water in the atmosphere.

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