Calculate the enthalpy change for the reaction, $$ \mathrm{XeF}_{4} \longrightarrow \mathrm{Xe}^{+}+\mathrm{F}^{-}+\mathrm{F}_{2}+\mathrm{F} $$ The average \(\mathrm{Xe}-\mathrm{F}\) bond energy is \(34 \mathrm{kcal} / \mathrm{mol}\), first I.E. of \(\mathrm{Xe}\) is 279 kcal/mol, electron affinity of \(\mathrm{F}\) is 85 kcal/ mol and bond dissociation energy of \(\mathrm{F}_{2}\) is \(38 \mathrm{kcal} / \mathrm{mol}\).

Bond energy is a measure of the strength of a chemical bond. It represents the amount of energy required to break one mole of bonds in a molecule in the gaseous state. To fully grasp this concept, consider a simple analogy: breaking a stick requires effort, just as breaking chemical bonds requires energy input. For the reaction

\(\mathrm{XeF}_{4} \longrightarrow \mathrm{Xe}^{+} + \mathrm{F}^{-} + \mathrm{F}_{2} + \mathrm{F}\), we need to break the xenon and fluorine bonds present within \(\mathrm{XeF}_{4}\). The given average \(\mathrm{Xe}-\mathrm{F}\) bond energy is \(34 \mathrm{kcal} / \mathrm{mol}\). Multiplying this energy by the number of bonds present provides the total energy absorbed to break these bonds.

Ionization energy refers to the energy required to remove an electron from an atom or ion in its gaseous phase. It quantifies the strength of the attraction between the nucleus and the electrons. Think of it as the energy you need to overcome the 'grip' that an atom has on its outermost electron. For example, the first ionization energy (I.E.) of xenon (Xe) is \(279 \mathrm{kcal/mol}\). It is higher than the bond energies we encounter because removing an electron from xenon involves overcoming the electrostatic force of attraction from the positively charged nucleus towards the negatively charged electron. The removal of this electron results in the formation of \(\mathrm{Xe}^{+}\), an important step in our reaction.

Electron affinity is the energy change that occurs when an electron is added to an isolated atom or molecule. In a way, it's the opposite of ionization energy. While ionization energy involves removing an electron, electron affinity measures the energy released when an atom gains an electron. It is often exothermic for nonmetals, as they have a higher tendency to gain electrons to achieve a stable electronic configuration. In our reaction, a fluorine atom gains an electron to form a fluoride ion (\(\mathrm{F}^{-}\)), with an electron affinity of \(85 \mathrm{kcal/mol}\), releasing energy that contributes to the overall exothermic process.

Bond dissociation energy is a specific type of bond energy that pertains to the energy required to break a bond in a molecule with more than two atoms. It is the energy required to separate one mole of a particular bond into the individual atoms, without causing the molecule to lose its molecular structure. An important distinction here is that it applies to a specific bond within a molecule, not all the identical bonds at once. In the context of our reaction, the \(\mathrm{F}_{2}\) molecule needs to be split into two F atoms, with a bond dissociation energy of \(38 \mathrm{kcal/mol}\). This is a critical step in the process, as it allows for the subsequent formation of \(\mathrm{F}^{-}\) and the free fluorine atom.