Specific Latent Heat of Vaporization vs Evaporation

[Peter G.]

Hi,

When studying and thinking about the concept of Specific Latent Heat of Vaporization I keep falling in the trap of confusing it with evaporation - in the end, in both cases water in the liquid state is being changed into vapor.

Could anyone help me differentiate the two ideas?

Thanks,
Peter G.

 

[rock.freak667]

Evaporation is the process by which a liquid is converted into a gas.

The specific latent heat is the energy per unit mass needed to convert something from a liquid to a gas.

 

[Peter G.]

Oh, ok. But we can only calculate the Specific Latent Heat of Vaporization when the temperature is the boiling point right? Or is it because the value we are usually given is the energy required for when the temperature, in the case of water, is 100 degrees Celsius?

 

[rock.freak667]

Oh, ok. But we can only calculate the Specific Latent Heat of Vaporization when the temperature is the boiling point right? Or is it because the value we are usually given is the energy required for when the temperature, in the case of water, is 100 degrees Celsius?

Well boiling and evaporation are both types of vaporization. Boiling just happens at one temperature and evaporation happens below that temperature.

Usually the specific latent heat of vaporization values you are given are measured at the boiling point.

So if you want to know the latent heat at some other temperature then you'd need to get the corresponding value.

 

[rwisz]

Dear Peter G.,

Thank you for your question about the difference between Specific Latent Heat of Vaporization and evaporation. Both of these terms refer to the process of water changing from a liquid state to a gaseous state, but there are some key differences between the two.

Specific Latent Heat of Vaporization refers to the amount of heat energy required to change a unit mass of a substance from liquid to gas at a constant temperature. In simpler terms, it is the amount of energy needed to convert a certain amount of liquid water into vapor.

On the other hand, evaporation refers to the process by which water molecules at the surface of a liquid gain enough energy to break free and enter the gas phase. This process occurs at any temperature, not just at a constant temperature like in the case of Specific Latent Heat of Vaporization.

In other words, Specific Latent Heat of Vaporization is a measure of the energy required for a specific amount of water to change from liquid to gas, while evaporation is a process by which water molecules gain enough energy to escape into the gas phase.

I hope this helps clarify the difference between these two concepts. Please let me know if you have any further questions.

Best,