Waec Model Questions Vol1 2024 Chemistry Question 9

Practice objective / multiple choice question 9 from the 2024 Waec Model Questions Vol1 Chemistry examination.

Waec Model Questions Vol1 2024 Chemistry Objective / Multiple Choice Medium Difficulty
Question 9 WAEC_MODEL_QUESTIONS_VOL1 • 2024 • CHEMISTRY • objective

The standard enthalpies of formation are: ΔH_f°(C₈H₁₈) = -250 kJ·mol⁻¹, ΔH_f°(CO₂) = -393.5 kJ·mol⁻¹, ΔH_f°(H₂O, l) = -285.8 kJ·mol⁻¹. Using Hess's law, calculate the heat released when 2.5 mol of octane (C₈H₁₈) combust completely in excess O₂. Express your answer in kilojoules, to three significant figures, and include the sign.

Answer Options

Correct Answer A. -1.37×10^4 kJ
B. -1.37×10^3 kJ
C. -1.25×10^4 kJ
D. -1.50×10^4 kJ
Correct Answer
A
Correct Option:
-1.37×10^4 kJ

About This Question

This is Waec Model Questions Vol1 2024 Chemistry Question 9. It is one of the objective questions from the 2024 Waec Model Questions Vol1 Chemistry examination.

Difficulty level: Medium .

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