The heat required during a change of state depends upon the heat of transformation and the mass of the substance undergoing a change of state. Thus, if mass m of a substance undergoes a change from one state to the other, then the quantity of heat required is given by

where L is known as latent heat and is a characteristic of the substance.

Its SI unit is J kg-1. The value of L also depends on the pressure.

Latent heat of Fusion:

The latent heat of fusion (Lf) is the heat per unit mass required to change a substance from solid into liquid at the same temperature and pressure.

Lf = 3.3 × 105 J kg-1

Latent heat of Vaporization:

The latent heat of vaporization (LV) is the heat per unit mass required to change a substance from liquid to the vapor state without the change in the temperature and pressure.

LV = 22.6 × 105 J

How useful was this post?

Click on a star to rate it!

Average rating 0 / 5. Vote count: 0

No votes so far! Be the first to rate this post.

As you found this post useful...

Follow us on social media!

We are sorry that this post was not useful for you!

Let us improve this post!

Tell us how we can improve this post? Please mention your Email so that we can contact you for better feedback.


Please enter your comment!
Please enter your name here