MCQ
The enthalpy change $(\Delta H)$ for the reaction, $N_2 (g) + 3H_2 (g) \to 2NH_3(g)$ is $-92.38\, kJ$ at $298\, K$. The internal energy change $\Delta U$ at $298\, K$ is .............. $\mathrm{kJ}$
  • A
    $-92.38$
  • $-87.42$
  • C
    $-97.34$
  • D
    $-89.9$

Answer

Correct option: B.
$-87.42$
b
$\Delta E = \Delta H - \Delta nRT$

$ =  - 92.38 - \left( {\frac{{ - 2 \times 8.31 \times 298}}{{1000}}} \right)$

$ =  - 92.38 + 4.95$

$ =  - 87.43\,kJ$

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