13. Specific latent heat

If \(Q\) is the amount of heat energy absorbed or released by the ‘m' mass of a substance during its phase change at a constant temperature, then the specific latent heat is given by

 

 

As a result, specific latent heat is the amount of heat energy absorbed or liberated by a unit mass without causing a temperature change during a state change. J/kg is the SI unit for specific latent heat.

 

Let us look at the example problem.

 

1. How much heat energy is required to melt 4 kg of ice? (Specific latent heat of ice = 336 J/g)

  

Given:

 

Mass (\(m\)) \(=\) \(4 kg\)

 

Specific latent heat of ice (\(L\)) \(=\) \(336 J/g\)

 

To find: Heat energy (\(Q\))