Question #302ef

May 25, 2017

$\Delta H = - 110.0$ $k J$/$m o l$ $C O$

Explanation:

First, write the reaction formulas.
$C \left(s\right) + {O}_{2} \left(g\right) \to C {O}_{2} \left(g\right)$, $\Delta {H}_{1} = - 393.5 k J \cdot m o {l}^{-} 1$ (1)
$2 C O \left(s\right) + {O}_{2} \left(g\right) \to 2 C {O}_{2} \left(g\right)$, $\Delta {H}_{2} = 2 \cdot \left(- 283.5\right) k J \cdot m o {l}^{-} 1$ (2)

The formula for the formation of carbon monoxide $C O$:
$C \left(s\right) + \frac{1}{2} {O}_{2} \to C O \left(g\right)$

Apply the Hess's law to find the enthalpy of formation of $C O$:
$\Delta {H}_{1}$-$\Delta {H}_{2}$
$= - 393.5 k J \cdot m o {l}^{-} 1 - \left(- 283.5 k J \cdot m o {l}^{-} 1\right)$
$= - 110.0 k J \cdot m o {l}^{-} 1$