Question

How do you solve the enthalpy problems?

Answer 1

Hint: We need to know that the enthalpy of fusion is also called the heat of fusion. The enthalpy of a fusion of a substance indicates the change in the enthalpy or heat developed from providing the energy. The particular amount of energy of a substance to change the phase of a material from solid state to liquid phase at a constant pressure. The enthalpy of the reaction can be found by adding the internal energy with the product of pressure and the volume and the enthalpy is represented as $'H'$.

Complete answer:
Usually the enthalpy change exists in a chemical reaction. The amount of heat released or absorbed during a chemical reaction is known as the enthalpy change. Let’s discuss the calculation method of enthalpy problems.
If the enthalpy of products and reactants are given, we can directly find out the enthalpy change by subtracting the enthalpy of reactant from the enthalpy of product. The formula is,
$\Delta H = {H_{Products}} - {H_{reactants}}$
The enthalpy change during the phase transition can be find out by using an another formula and that is,
$\Delta H = nc\Delta T$
When the compound changes from one phase to another, a specific enthalpy changes. Then, the number of molecules (n), change in temperature $\left( {\Delta T} \right)$ and specific heat (c) will be given. By converting those values, we can calculate the enthalpy change.

Note:
The quantity of heat energy for the conversion of the definite mass of a solid at its melting point to the liquid is known as enthalpy of fusion. In that process, there will not increase the temperature. Normally, the chemical reaction will undergo the enthalpy change. Sometimes, we can directly calculate the enthalpy change by subtracting the values of enthalpy of products and the reactant.