Question

Define the following term Enthalpy of fusion.

Answer 1

First, we understood about luster. In mineralogy luster describes how light is reflected on the surface of minerals. We also remember that the luster is the most important property to determine the identity of a mineral.

Complete step by step answer:
First, we see what is enthalpy of a reaction is.
Enthalpy:
The heat of reaction or the enthalpy change is defined as the energy absorbed or released in any reaction.
If energy is absorbed by the reaction it is said to be endothermic and is positive and more energy is needed to break the bonds and the reactants are lower in energy than the products.
If energy is released by the reaction is said to be exothermic and is negative and more energy is released while forming bonds and the energy of the product is lower than the reactants.
Now, we discuss the enthalpy of fusion.
Enthalpy of fusion:
The heat which a solid absorbs when it melts is termed the enthalpy of fusion or heat of fusion and is sometimes quoted on a molar basis. For instance, when $1{\text{ }}mol$ of ice is melted, we discover the molar enthalpy of fusion of ice is$+ 6.01{\text{ }}kJmo{l^{-1}}$, and we can write that as,
${H_2}O\left( s \right)\xrightarrow{{{0^ \circ }C}}{H_2}O\left( l \right) \\\ \\\$
$\Delta {H_m} = 6.01\,kJ/mol$

Note:
Now we discuss the enthalpy of vaporization.
Enthalpy of vaporization:
When a liquid is boiled, the difference of temperature with the heat supplied is analogous to that found for melting. When heat is supplied at a gentle rate to a liquid at air pressure, the temperature rises until the boiling point is attained. After the boiling point the temperature remains constant until the enthalpy of vaporization $(\Delta Hm)$ is supplied and again the temperature rises once all the liquid has been converted to vapor. In such cases of water the molar enthalpy of vaporization is $40.67{\text{ }}kJ{\text{ }}mo{l^{ - 1}}$ .