Given the bond enthalpies Cl-Cl (243), C-Cl (339), H-Cl (431),C-H (414) all in kJ/mol, estimate ΔH for the following reaction: CH₄(g) + Cl₂(g) → CH₃Cl(g) + HCl(g)

Question

Quizplus · Accepted Answer

The correct answer is A because the ΔH for the reaction can be calculated as follows:ΔH = Σ(bond enthalpies of reactants) - Σ(bond enthalpies of products)ΔH = [4(H-Cl) + C-H + Cl-Cl] - [3(H-Cl) + C-Cl + C-H]ΔH = [4(431) + 414 + 243] - [3(431) + 339 + 414]ΔH = [1724 + 414 + 243] - [1293 + 339 + 414]ΔH = 2381 - 2046ΔH = -113 kJ

Given the Bond Enthalpies Cl-Cl (243), C-Cl (339), H-Cl (431),C-H