Vapor pressure and the boiling point of a liquid

In summary, There is a correlation between vapor pressure and boiling point of a substance, with the boiling point being the temperature at which the vapor pressure is equal to the atmospheric pressure. This is due to the requirement for equilibrium rates of evaporation and condensation in the boiling bubbles. The expression "kinetic energy of the interior of the liquid begins to become gaseous" does not make sense as kinetic energy does not have states.
  • #1
That Neuron
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0
I'm not totally sure this topic should be placed in this forum, since it is not specifically solid state.

Anyways, my question is simply why is there a correlation between vapor pressure and the boiling point of a substance, I would have thought that the boiling point would be at any temperature that the kinetic energy of the interior of the liquid begins to become gaseous.

Is it because the vapor must stop cooling the liquid at the atmospheric pressure.
 
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  • #2
At the boiling point (which depends on the atmospheric pressure) the vapor pressure is equal to the atmospheric pressure.

The expression "the kinetic energy of the interior of the liquid begins to become gaseous" does not make much sense. I am not sure what do you mean. The kinetic energy does not have states, like liquid or gas, does it?
 
  • #3
When you refer to "vapor pressure" as equal to atmospheric pressure at boiling point:

Do you use the words as "equilibrium vapor pressure"? If so, why the requirement for equilibrium rates of evaporation and condensation of liquid-vapor in the boiling bubbles?
 

1. What is vapor pressure?

Vapor pressure is the pressure exerted by the vapor of a liquid in a closed container at a given temperature. It is a measure of the tendency of molecules in a liquid to escape into the gas phase.

2. How does vapor pressure affect the boiling point of a liquid?

Vapor pressure and boiling point are directly related. As the vapor pressure of a liquid increases, so does its boiling point. This is because a higher vapor pressure means that more molecules are escaping into the gas phase, making it harder for the remaining liquid molecules to overcome the external pressure and boil.

3. What factors affect the vapor pressure of a liquid?

The vapor pressure of a liquid depends on its temperature, intermolecular forces, and the properties of the surrounding environment (such as air pressure and temperature).

4. Can the vapor pressure of a liquid exceed atmospheric pressure?

Yes, the vapor pressure of a liquid can exceed atmospheric pressure. This is known as superheating and can occur when a liquid is heated in a sealed container, causing the vapor pressure to build up until it reaches a point where it exceeds the external pressure.

5. How does altitude affect the boiling point of a liquid?

As altitude increases, the atmospheric pressure decreases. This means that the external pressure on a liquid is also lower, making it easier for the liquid molecules to escape into the gas phase. As a result, the boiling point of a liquid decreases at higher altitudes.

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