Question

Which equation has an enthalpy change of reaction which corresponds to the standard enthalpy change of atomisation of chlorine?
A) $\quad \dfrac{1}{2} \mathrm{Cl}_{2}(\mathrm{~g}) \rightarrow \mathrm{Cl}(\mathrm{g})$
B) $\dfrac{1}{2} \mathrm{Cl}_{2}(\mathrm{l}) \rightarrow \mathrm{Cl}(\mathrm{g})$
C) $\mathrm{Cl}_{2}(\mathrm{~g}) \rightarrow 2 \mathrm{Cl}(\mathrm{g})$
D) $\quad \mathrm{Cl}_{2}(1) \rightarrow 2 \mathrm{Cl}(\mathrm{g})$

Answer 1

A thermodynamic system's enthalpy is defined as the sum of the system's internal energy and the product of its pressure and volume. It's a state function that's utilised in a variety of measurements in chemical, biological, and physical systems under constant pressure, which the vast ambient environment easily provides.

Complete answer:
The change in enthalpy during the production of 1 mole of a material from its component elements, with all substances in their standard states, is known as the standard enthalpy of formation or standard heat of formation.
Every naturally occurring process results in the creation of new goods. Some of the processes we are aware of absorb energy, while others result in energy evolution. As a result, when operations are completed, we always notice a shift in enthalpy. The enthalpy of atomization, solution, and other processes can cause this shift in enthalpy.
When a compound's bonds are broken and the component atoms are split into individual atoms, the enthalpy of atomization is the amount of enthalpy change. The symbol for enthalpy of atomization is ${{\Delta }_{at}}H$. The sum of the H–O–H and H–O bond dissociation enthalpies, for example, is the enthalpy change of atomization of gaseous ${{H}_{2}}O$ . The enthalpy of atomization of an elemental solid is the same as the enthalpy of sublimation of any elemental solid that evaporates into a monatomic gas.
Because the conventional enthalpy change is predicated only on the generation of one mole of gaseous atoms, only half a mole of molecules will be required to convert a diatomic element to gaseous atoms. The computation becomes more difficult when the atoms in the molecule are different isotopes of the same element.
The enthalpy change when 1 mol of a material is fully split into atoms under normal circumstances is called standard enthalpy of atomization (298.15K, 1 bar).
The aforementioned reaction's enthalpy change is the same as the conventional enthalpy change of chlorine atomization $\quad \dfrac{1}{2} \mathrm{Cl}_{2}(\mathrm{~g}) \rightarrow \mathrm{Cl}(\mathrm{g})$
Hence option A is correct.

Note:
The change in enthalpy is proportional to the change in a system's internal energy when pressure is held constant. As a result, the total of the fusion and vaporisation enthalpies equals the atomization enthalpy. Sc and Zn are members of the pf group's third periodic table. The atomization enthalpy is influenced by the degree of metallic bonding that an element has. The greater the extent of an element's metallic bonding, the higher the atomization enthalpy.