Question

How can I calculate the enthalpy of fusion?

Answer 1

Hint The enthalpy of fusion of a substance is nothing but the amount of heat required to convert a substance from its solid state to liquid state by keeping the pressure constant. Enthalpy of fusion is also called heat of fusion.

Complete answer:
- In the question it is asked to calculate the enthalpy of fusion.
- Enthalpy of fusion or heat of fusion of a substance is going to depend on the degree of crystalline nature of the substance.
- The formula to calculate the enthalpy of fusion of heat of fusion is as follows.
$q=m.\Delta {{H}_{f}}$
Here q = heat energy
m = mass of the substance
$\Delta {{H}_{f}}$ = Heat of fusion or enthalpy of fusion.
- The liquid state will have a high amount of internal energy when compared to solid state.
- The molecules in liquid state experience weaker force of intermolecular attraction and have high potential energy.
- The enthalpy of fusion also called as latent heat of fusion.
- The change in state from solid to liquid is called melting, by applying heat of fusion, melting of the solid substance happens.

Note: We have to supply some amount of heat to a substance to make it liquid and when this liquid is going to fuse it releases the amount of heat absorbed in the name of heat of fusion. The heat of fusion will always be a positive number for all the molecules except helium, it has a negative heat of fusion.