Question

The heat of formations of CO_(g) and CO_2(g) are −26.4 kcal and −94.0 kcal respectively. The heat of combustion of carbon monoxide will be ____________.

Options

• +26.4 kcal

• −67.6 kcal

• −120.6 kcal

• +52.8 kcal

Answer 1

The heat of formations of CO_(g) and CO_2(g) are −26.4 kcal and −94.0 kcal respectively. The heat of combustion of carbon monoxide will be −67.6 kcal.

Explanation:

\[\ce{CO + 1/2O2 -> CO2}\]

∆H = `∆_"f""H"^0 ("CO"_2) - [∆_"f""H"^0 ("CO") + 1/2∆_"f""H"^0 ("O"_2)]`

∴ = −94.0 kcal − (−26.4 kcal) ........[∵ ∆_fH⁰(O₂) = 0]

= −67.6 kcal