Waec Model Questions Vol1 2017 Chemistry Question 20

Practice objective / multiple choice question 20 from the 2017 Waec Model Questions Vol1 Chemistry examination.

Waec Model Questions Vol1 2017 Chemistry Objective / Multiple Choice Hard Difficulty
Question 20 WAEC_MODEL_QUESTIONS_VOL1 • 2017 • CHEMISTRY • objective

Consider the reaction of solid tetraphosphorus with chlorine gas: P₄(s) + 6 Cl₂(g) → 4 PCl₃(g). The bond dissociation energies are: P-P in P₄ = 200 kJ mol⁻¹ (six such bonds per P₄ molecule), Cl-Cl = 243 kJ mol⁻¹, and P-Cl = 320 kJ mol⁻¹. The enthalpy of vapourisation of P₄(s) to P₄(g) is 30 kJ mol⁻¹. Using these data, calculate the net enthalpy change per mole of PCl₃ formed and state whether the reaction is exothermic or endothermic.

Answer Options

Correct Answer A. -288 kJ·mol⁻¹ (exothermic)
B. -150 kJ·mol⁻¹ (exothermic)
C. +288 kJ·mol⁻¹ (endothermic)
D. -288 kJ·mol⁻¹ (endothermic)
Correct Answer
A
Correct Option:
-288 kJ·mol⁻¹ (exothermic)

About This Question

This is Waec Model Questions Vol1 2017 Chemistry Question 20. It is a objective / multiple choice question from the 2017 Waec Model Questions Vol1 Chemistry examination.

Difficulty level: Hard .

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