Heat Of Fusion Formula

Heat Of Fusion Formula

The Heat Of Fusion Formula of any substance is an important calculation of heat. This is the change in the value of enthalpy due to the application of energy, or heat, to a given amount of matter. It changes from solid to liquid while keeping the pressure constant. The heat of fusion of a sample measures the amount of heat that must be introduced to transform its crystalline fraction into a disordered state. This topic explains the Heat Of Fusion Formula with an example of the concept of fusion heat.

“Heat of fusion” measures the amount of energy required to melt a given amount of solid at its melting point temperature. In other words, it also represents the amount of energy released when a certain mass of liquid freezes. For example, the heat of the melting of water is 80 calories per gram. This means that it takes 80 calories of energy to melt 1 gram of ice at 0 °C in water at 0 °C, and it depends on the material. For example, we know that the heat gained from ice is equal to the heat lost from water. The Heat Of Fusion Formula is denoted by the symbol ΔHf.

When a solid enters a liquid, that’s what we know as melting. This melting process requires an increase in energy so that the solid particles can separate from each other, and this energy input is the heat of fusion. The Heat Of Fusion Formula is not the same for all substances but is a constant value for each type of substance. Students can also check the Extramarks website for examples and formulas of different topics like the Heat Of Fusion Formula.

Concept Of The Heat Of Fusion

Determining the Heat Of Fusion Formula is fairly straightforward. Once the solid melts or freezes, the temperature remains constant until the entire phase change is complete. You can visualize this process by examining the heating/cooling diagram. By plotting this figure before running a heat of fusion analysis, you can easily plan the steps necessary to complete the analysis.

The heat of the melting process can be observed in myriad applications and can be demonstrated in the manufacture of many common household items. As mentioned at the beginning, the most common use of Heat Of Fusion Formula is to melt ice into water. 

The Formula For The Heat Of Fusion:

In coinage, solid zinc and copper (the metals of the American penny denomination) are placed in a casting furnace and heated by the Heat Of Fusion Formula until they reach a liquid phase. In the liquid phase, molten zinc and copper are poured into a mould and cast into long bars. During the casting process, the molten metal changes from a liquid phase to a solid phase, resulting in a solid ingot. The long sticks are flattened by heavy machinery and minted into thousands of coins. 

Solved Examples For Heat Of Fusion Formula

Q.1: Calculate the amount of heat in joules required to melt 26 grams of ice. Here it is stated that the Heat Of Fusion Formula of water is 334 J/g. H. Equivalent to 80cal per gram.

Solution: the given parameters are

Mass, m = 26 g

we know that,

ΔHf = square meter

change the formula to



= 8684 joules.

Therefore, the required heat is 8684 Joules.

Q.2: What is the Heat Of Fusion Formula of water if 668 joules of heat energy is required to melt 2 grams? Solution: Known values ​​are

Q = 668 joules

and M = 2 grams

The formula is:

ΔHf = square meter


= 334 J per gram.

Therefore, the heat of fusion is 334 J per gram.

Q.3: When 1500 J of heat energy is applied, what is the mass of water that will melt at 0 degrees Celsius?

Solution: Here the heat of fusion is for water and the equation needs to be rearranged to solve for the mass. This is Hf=1500J

Q = 334C per gram

ΔHf = square meter




= 4.49 grams

The mass of water is 4.49 grams.

Physics Related Formulas
Projectile Motion Formula Combustion Formula
Strain Formula Continuous Compound Interest Formula
Efficiency Formula Heat Loss Formula
Magnetic Flux Formula Inverse Square Law Formula
Reynolds Number Formula Momentum Of Photon Formula
Terminal Velocity Formula Orbital Speed Formula
Bulk Modulus Formula Polarization Formula
Current Density Formula Tangential Velocity Formula
De Broglie Wavelength Formula Air Resistance Formula
Electric Current Formula Coefficient Of Static Friction Formula