Consider the gas-phase reaction: with an overall kJ. Using average bond energies and kJ/mol, calcula — Thermodynamics and Thermochemistry Chemistry Question
Question
Consider the gas-phase reaction: $XeF_2(g) + H_2(g) \rightarrow 2HF(g) + Xe(g)$ with an overall $\Delta H^\circ = -430$ kJ. Using average bond energies $BE(H-H) = 435$ and $BE(H-F) = 565$ kJ/mol, calculate the average bond energy of the $Xe-F$ bond.
Answer: A
💡 Solution & Explanation
From bond energies: $\Delta H_{rxn} = \sum BE(reactants) - \sum BE(products)$. Thus, $-430 = [2 \times BE(Xe-F) + BE(H-H)] - [2 \times BE(H-F)]$. Substitute values: $-430 = 2 \times BE(Xe-F) + 435 - 2(565)$. Solving gives $2 \times BE(Xe-F) = 265 \Rightarrow BE(Xe-F) = 132.5$ kJ/mol.
💬Ask on WhatsApp →
Still have doubts about this question?
Send it to our AI chemistry tutor on WhatsApp — gets answered in minutes