Gce Model Questions Vol1 2019 Chemistry Question 19

Practice objective / multiple choice question 19 from the 2019 Gce Model Questions Vol1 Chemistry examination.

Gce Model Questions Vol1 2019 Chemistry Objective / Multiple Choice Hard Difficulty
Question 19 GCE_MODEL_QUESTIONS_VOL1 • 2019 • CHEMISTRY • objective

Using the following bond‑dissociation energies (kJ mol⁻¹): D(H-H)=436, D(Cl-Cl)=243, D(Br-Br)=193, D(H-Cl)=431, D(H-Br)=366. Calculate the enthalpy change for the reactions (1) \(\mathrm{H_2 + Cl_2 \rightarrow 2\,HCl}\) and (2) \(\mathrm{H_2 + Br_2 \rightarrow 2\,HBr}\) by the bond‑energy method, then state which reaction is more exothermic and by how much.

Answer Options

A. ΔH₁ = -180 kJ·mol⁻¹; ΔH₂ = -120 kJ·mol⁻¹; reaction (1) is more exothermic by 60 kJ·mol⁻¹
Correct Answer B. ΔH₁ = -183 kJ·mol⁻¹; ΔH₂ = -103 kJ·mol⁻¹; reaction (1) is more exothermic by 80 kJ·mol⁻¹
C. ΔH₁ = -190 kJ·mol⁻¹; ΔH₂ = -95 kJ·mol⁻¹; reaction (1) is more exothermic by 95 kJ·mol⁻¹
D. ΔH₁ = -170 kJ·mol⁻¹; ΔH₂ = -110 kJ·mol⁻¹; reaction (1) is more exothermic by 60 kJ·mol⁻¹
Correct Answer
B
Correct Option:
ΔH₁ = -183 kJ·mol⁻¹; ΔH₂ = -103 kJ·mol⁻¹; reaction (1) is more exothermic by 80 kJ·mol⁻¹

About This Question

This is Gce Model Questions Vol1 2019 Chemistry Question 19. It is one of the objective questions from the 2019 Gce Model Questions Vol1 Chemistry examination.

Difficulty level: Hard .

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