Latent Heat of Fusion Formula

Introduction to Latent Heat of Fusion

We often hear since childhood that a block of ice melts to give chilled water; we also talk about the water turning to steam, which is used for rotating turbines and generating electricity.

However, we come across the phenomenon when we study science. This article discusses the latent heat of fusion formula.

So, latent heat of fusion is the amount of inner or latent heat a solid gains (melting) to transform into a liquid state or the liquid state to gaseous (boiling). 

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Latent Heat of Fusion Meaning

Latent heat means the energy required to change an object’s state. Fusion means combination. Overall, latent heat of fusion means the added energy or heat because of which an object changes to another state.

Here, it is about the transformation of solid to liquid, which is melting and liquid to a gaseous state, which is called the boiling process.


Heat and Temperature

Under the chapter on Thermodynamics, we represent a parameter heat by an English block letter ‘Q’. We often jumble the word ‘heat’ with ‘temperature’; however, these two terms have huge differences.

Heat is the effect of an object generating vibrations in particles inside the object. We also consider heat as the rise in entropy of particles or the kinetic energy of these under the effect of rising temperatures.

Temperature is something that can be both high and low, while heat is always rising.

Now, when the heat is latent, for example, you have an inner heat and when you sleep, your body reaches the Gibbs’ free energy state because that time your body loses heat and its temperature falls. 


Latent Heat of Fusion Formula

So, the formula of latent heat of fusion is given by:

△Q = mL, which is the required equation for the latent heat of fusion

Here, 

△Q = change in heat energy in Joules

m = mass in Kg

L = Specific latent heat of fusion

So, do you know what the specific latent heat of fusion is?


Specific Latent Heat of Fusion 

We define the specific latent heat as the energy required to transform or change the state of 1 kg of substance.

However, the specific latent heat of fusion is the energy needed to melt a kilogram of substance. 

There is another term called the specific latent heat of vaporization. We define the specific latent heat of vaporization as the energy required to boil or evaporate a kilogram of substance.

However, the formula for Specific Latent Heat of Fusion is


Specific Latent Heat of Fusion Formula

The formula of specific latent heat of fusion is given by:

Q = mL, which is the required specific latent heat of fusion equation. 


Specific Latent Heat of Fusion Equation

We define the specific latent heat of fusion equation in the following manner:

If ‘m’ kg of solid substance changes to liquid state at a constant temperature, which is its melting point, the heat absorbed by the substance or the latent heat of fusion formula is given by:

Q = m L

Where,

L = specific latent heat of fusion of substance that is measured in Joule per kilogram or J/kg.


Conclusion

A matter transforms from one state to another because of a hidden heat, which is latent. If energy is added to rise by 1 kg, it is the specific latent heat of fusion. Both are measured in J/kg.


FAQs (Frequently Asked Questions)

1. Define specific heat.

The word ‘specific heat’ talks about an object being heated specifically by one degree. So, basically, the specific heat capacity of a solid is defined as the amount of heat needed to raise the temperature of a unit mass of the substance by one degree. 


The unit for measuring the specific heat is J/kg-°C.

2. What do you mean by specific heat at constant volume and constant volume?

Specific Heat at Constant Volume and Constant Pressure are intensive properties denoted by cV and cP, respectively; these properties are defined for pure, simple, and compressible substances.

3. Specify latent heat of fusion.

The energy needed to entirely separate the molecules, moving from liquid to gas is much greater than if you were just to reduce their separation from solid to liquid.