What is $\Delta$ H_rxn° for the reaction: 2 CO(g) + O₂(g) $\rightarrow$ 2 CO₂(g) if:
C(s) + 1/2 O₂(g) $\rightarrow$ CO(g) $\Delta$ H_rxn° = -111 kJ/mol_rxn
C(s) + O₂(g) $\rightarrow$ CO₂(g) $\Delta$ H_rxn° = -393 kJ/mol_rxn

Question

What is

\Delta

H_rxn° for the reaction: 2 CO(g) + O₂(g)

\rightarrow

2 CO₂(g) if:
C(s) + 1/2 O₂(g)

\rightarrow

CO(g)

\Delta

H_rxn° = -111 kJ/mol_rxn
C(s) + O₂(g)

\rightarrow

CO₂(g)

\Delta

H_rxn° = -393 kJ/mol_rxn

Quizplus · Accepted Answer

The reaction can be derived using Hess's Law: 2(C + O2 → CO2) - 2(C + 1/2 O2 → CO) = 2 CO + O2 → 2 CO2. Thus, ΔH° = 2(-393) - 2(-111) = -564 kJ/mol.

What Is Δ\DeltaΔ Hrxn° for the Reaction: 2 CO(g) + O2(g) →\rightarrow→