The **key difference **between latent heat of fusion and vaporization is that **latent heat of fusion is the amount of heat that a solid substance requires to change its phase from solid phase to liquid phase at a constant temperature whereas latent heat of vaporization is the amount of heat that a liquid substance requires to change its phase from liquid phase to vapor phase at a constant temperature.**

Latent heat of fusion and vaporization refers to the change in heat energy at constant temperatures. The latent heat of fusion describes the change in heat at a substance’s melting point. On the contrary, latent heat of vaporization describes the change in heat at the boiling point of a substance. Likewise, there are some differences between the two chemical concepts.

### CONTENTS

1. Overview and Key Difference

2. What is Latent Heat of Fusion

3. What is Latent Heat of Vaporization

4. Side by Side Comparison – Latent Heat of Fusion vs Vaporization in Tabular Form

5. Summary

## What is Latent Heat of Fusion?

Latent heat of fusion is the amount of heat that a solid substance requires to change its phase from solid phase to liquid phase at a constant temperature, denoted by H_{f}. In other words, a unit mass of a substance requires a heat energy that is equal to the latent heat of fusion (of that particular substance) at its melting point, in order to convert into its liquid phase. Fusion is melting (liquefying a solid by providing heat). Different substances have different melting points; thus, different values for H_{f}.

### Equation of Latent Heat of Fusion

The equation for H_{f} is as follows:

**H _{f} =ΔQ_{f}/ m**

Here, ΔQ_{f}is the change in the energy of the substance and m is the mass of the substance.

## What is Latent Heat of Vaporization?

Latent heat of vaporization is the amount of heat that a liquid substance requires to change its phase from the liquid phase to vapor phase at a constant temperature, denoted by H_{v}. In other words, a unit mass of a substance requires a heat energy that is equal to the latent heat of vaporization (of that particular substance) at its boiling point, in order to convert into its gas phase.

### Equation of Latent Heat of Vaporization

The equation for H_{v} is as follows:

**H _{v} =ΔQ_{v}/ m**

Here ΔQ_{v} is the change in the energy of the substance and m is the mass of the substance.

## What is the Difference Between Latent Heat of Fusion and Vaporization?

Latent heat of fusion is the amount of heat that a solid substance requires to change its phase from solid phase to liquid phase at a constant temperature while Latent heat of vaporization is the amount of heat that a liquid substance requires to change its phase from the liquid phase to vapor phase at a constant temperature.

Latent heat of fusion is denoted by H_{f }while latent heat of vaporization is denoted by H_{y }. With regard to the constant temperature, latent heat of fusion is to the change in heat at the melting point of a substance whereas the latent heat of vaporization refers to the change in heat at the boiling point of a substance.

## Summary – Latent Heat of Fusion vs Vaporization

Latent heat refers to the change in heat at a constant temperature. Different substances have different latent heats at their melting points and boiling points. The difference between latent heat of fusion and vaporization is that a substance changes its phase from solid to liquid when we provide an amount of heat that is equal to the latent heat of fusion whereas a substance changes its phase from liquid to vapor when we provide an amount of heat that is equal to latent heat of vaporization.

##### Reference:

1. “Latent Heat.” Ohm’s Law. Available here

2. “You Are Being Redirected…” Physics Theories Laws Basic Concepts & Resources with All Branches. Available here

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