Using the table of bond dissociation energies, the ΔH for the following reaction is __________ kJ. 2HCl (g)+ F₂ (g)→ 2HF (g)+ Cl₂ (g) A)-359 B)-223 C)359 D)223 E)208

Question

Quizplus · Accepted Answer

The ΔH for a reaction can be calculated using bond dissociation energies of the bonds being broken and formed in the reaction. Breaking the bond between H and Cl requires 431 kJ/mol, and breaking the bond between F and S requires 327 kJ/mol. Forming the bond between H and F releases 565 kJ/mol, and forming the bond between Cl and S releases 253 kJ/mol. Therefore, the overall enthalpy change of the reaction is:
(2 x 431) + (327) – (2 x 565) – (253) = -718 kJ/mol
However, the reaction equation is balanced, and the question is asking for the heat released per mole of 2HCl reacted, so the value needs to be divided by 2, giving -359 kJ/mol. Therefore, the correct answer is A.

Using the Table of Bond Dissociation Energies, the ΔH for the Following