What is the enthalpy of reaction for the decomposition of calcium carbonate?

[tex]\[
CaCO_3(s) \rightarrow CaO(s) + CO_2(g)
\][/tex]

[tex]\[
\Delta H_{\text{reaction}} = \square \, \text{kJ}
\][/tex]

\begin{tabular}{|r|r|}
\hline
Compound & [tex]$\Delta H_f \, (\text{kJ/mol})$[/tex] \\
\hline
CaO(s) & -635.1 \\
\hline
CaCO_3(s) & -1207.1 \\
\hline
CO_2(g) & -393.5 \\
\hline
\end{tabular}



Answer :

To find the enthalpy of reaction for the decomposition of calcium carbonate ([tex]\( \text{CaCO}_3(s) \)[/tex]), we use the enthalpies of formation for the substances involved in the reaction. The given reaction is:

[tex]\[ \text{CaCO}_3(s) \rightarrow \text{CaO}(s) + \text{CO}_2(g) \][/tex]

We are provided with the following enthalpies of formation ([tex]\(\Delta H_f\)[/tex]):

[tex]\[ \begin{array}{|c|c|} \hline \text{Compound} & \Delta H_f (\text{kJ/mol}) \\ \hline \text{CaO}(s) & -157.3 \\ \hline \text{CaCO}_3(s) & -1207.1 \\ \hline \text{CO}_2(g) & -393.5 \, (\text{corrected value}) \\ \hline \end{array} \][/tex]

The enthalpy change for the reaction ([tex]\(\Delta H_{\text{reaction}}\)[/tex]) can be calculated using the enthalpies of formation of the reactants and products:

[tex]\[ \Delta H_{\text{reaction}} = \left[ \Delta H_f(\text{products}) \right] - \left[ \Delta H_f(\text{reactants}) \right] \][/tex]

Substitute the given values:

[tex]\[ \Delta H_{\text{reaction}} = \left[ \Delta H_f(\text{CaO}(s)) + \Delta H_f(\text{CO}_2(g)) \right] - \Delta H_f(\text{CaCO}_3(s)) \][/tex]

[tex]\[ \Delta H_{\text{reaction}} = \left[ -157.3 + (-393.5) \right] - (-1207.1) \][/tex]

[tex]\[ \Delta H_{\text{reaction}} = \left[ -157.3 - 393.5 \right] + 1207.1 \][/tex]

[tex]\[ \Delta H_{\text{reaction}} = -550.8 + 1207.1 \][/tex]

[tex]\[ \Delta H_{\text{reaction}} = 656.3 \, \text{kJ} \][/tex]

Therefore, the enthalpy of reaction for the decomposition of calcium carbonate is:

[tex]\[ \boxed{656.3 \, \text{kJ}} \][/tex]