Question

The following reaction plays a key role in the destruction of ozone in the atmosphere:Cl (g) + O3 (g) -------> ClO (g) + O2 (g)

Answer 1

Answer: the entropy change for the reaction given is 19.9 J/K

Step-by-step explanation:

The question requires us to calculate the entropy change (ΔS) for the following reaction, given the standard molar entropies for ClO, O3, O2 and Cl:

`Cl_((g))+O_(3(g))\rightarrow ClO_((g))+O_(2(g))`

We can calculate the entropy change for a chemical reaction considering the "products minus reactants" rule. In this case, we'll need to calculate the sum of entropies for the reactants and then subtract it from the sum of entropies for the products, as given by the following equation:

`\Delta S_(rxn)=\sum^mS(products)-\sum_^nS(reactants)`

(m and n corresponds to the stoichiometric coefficients of products and reactants, respectively, as given by the balanced chemical equation).

Since the question provided the values of standard molar entropy for each reactant and product, we can calculate the entropy change as it follows (note that the stoichiometric coefficients in the reaction are 1 for all products and reactants, thus they weren't shown in the calculation as they do not change the result):

`\begin{gathered} \Delta S_(rxn)=[218.9+205.0]-[165.2+238.8] \\ \Delta S_(rxn)=423.9-404.0 \\ \Delta S_(rxn)=19.9\text{ J/K} \end{gathered}`

Therefore, the entropy change for the reaction given is 19.9 J/K.