2CO(g) + O\(_2\)(g) → 2CO\(_2\)(g) Given that ΔH[CO]is -110.4 kJmol-1 and ΔH[CO\(_2\)] is -393.0 kJmol-1,...

JAMB 2004

2CO(g) + O\(_2\)(g) → 2CO\(_2\)(g)
Given that ΔH[CO]is -110.4 kJmol-1 and ΔH[CO\(_2\)] is -393.0 kJmol-1, the energy change for the reaction above is

A. -503.7 kJ
B. -282.6 kJ
C. +282.6 kJ
D. +503.7 kJ

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Correct Answer: Option B

Explanation

Energy change = ΔH\(_{product}\) - ΔH\(_{reactants}\)

Given: ΔH\(_{CO_2}\) = - 393, ΔH\(_{CO}\) = - 110.4 , ΔH\(_{O_2}\) = 0 (The standard enthalpy of formation for molecular oxygen (O\(_2\)) is zero because oxygen in its diatomic form (O\(_2\)) is the most stable form of oxygen under standard conditions).

Energy change (ΔH) = ΔH\(_{CO_2}\) - (ΔH\(_{CO}\) + ΔH\(_{O_2}\))
= - 393 - ( - 110.4 + 0)
= - 393 + 110.4

= -282.6 kJ

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