Question #44223

To investigate the thermodynamic stability of high oxidation state fluorides, a student models the formation of gaseous sulfur hexafluoride, $\ce{SF6(g)}$, using a hypothetical gas-phase ionic Born-Haber cycle. The student assumes the formation of isolated $\ce{S^{6+}(g)}$ and $\ce{F^{-}(g)}$ ions, which then condense to form the covalent $\ce{SF6(g)}$ molecule. Given the following thermodynamic data at 298 K: Standard enthalpy of formation of $\ce{SF6(g)}$, $\Delta_f H^\circ = -1209 \text{ kJ/mol}$ Enthalpy of atomization of $\ce{S(s)}$, $\Delta_{atom} H^\circ = 277 \text{ kJ/mol}$ Bond dissociation enthalpy of $\ce{F2(g)}$, $\Delta_{diss} H^\circ = 159 \text{ kJ/mol}$ Sum of the first six ionization enthalpies of $\ce{S(g)}$, $\sum_{i=1}^6 IE_i = 27700 \text{ kJ/mol}$ Electron gain enthalpy of $\ce{F(g)}$, $\Delta_{eg} H^\circ = -328 \text{ kJ/mol}$ Calculate the hypothetical 'gas-phase condensation enthalpy' ($\Delta_{cond} H^\circ$) in kJ/mol—the energy released when one mole of $\ce{S^{6+}(g)}$ and six moles of $\ce{F^{-}(g)}$ combine to form one mole of $\ce{SF6(g)}$.