Question

($\Delta$H - $\Delta$U) for the formation of carbon monoxide (CO) from its elements at 298 K is
$(R = 8 \cdot 314 \,JK^{-1}\, mol{-1})$

• A. $- 1238.78 \,J \,mol^{-1}$
• B. $1238.78 \,J \,mol^{-1}$
• C. $- 2477.57\, J \,mol^{-1}$
• D. $2477.57 \,J \,mol^{-1}$

Answer 1

Answer: (B)

$\Delta H - \Delta U = \Delta n_{g} RT$
$= + \frac{1}{2}\times8.314 \times 298$
$= +\,\, 1238.78\,J\,mol^{-1}$
$\begin{bmatrix}C\left(S\right)+\frac{1}{2}O\,2\left(g\right)\to CO\,\left(g\right)\\ \Delta n_{g} = 1-\frac{1}{2}\\ = \frac{1}{2}\end{bmatrix}$