Question

The reaction in which $\Delta H > \Delta U$ is

• A. $N_{2\left(g\right)} + 3H_{2\left(g\right)} \to 2NH_{3(g)}$
• B. $CH_{4\left(g\right) }+ 2O_{2\left(g\right)} \to CO_{2\left(g\right)} + 2H_{2}O_{\left(l\right)}$
• C. $N_{2\left(g\right)} + O_{2\left(g\right)} \to 2NO_{\left(g\right)}$
• D. $CaCO_{3\left(S\right)} \to CaO_{\left(S\right)} + CO_{2\left(g\right)}$

Answer 1

Answer: (D)

$CaCO_{3\left(S\right)} \to CaO_{\left(S\right)} + CO_{2\left(g\right)}$

Answer 2

$CaCo_{3\left(s\right)} \to CaO_{\left(s\right)}+Co_{2\left(g\right)}$
$\Delta n=+1$
$\Delta H=\Delta U+\Delta n_{g}RT$
$\Delta H>\, \Delta U$