Which of the following reactions shows that the formation of [tex]\( CO_2 \)[/tex] releases [tex]\( 393.5 \, \text{kJ/mol} \)[/tex]?

A. [tex]\( C(s) + O_2(g) + 393.5 \, \text{kJ} \rightarrow CO_2(g) \)[/tex]

B. [tex]\( C(s) + 2O(g) + 393.5 \, \text{kJ} \rightarrow CO_2(g) \)[/tex]

C. [tex]\( C(s) + O(g) \rightarrow CO_2(g) + 393.5 \, \text{kJ} \)[/tex]

D. [tex]\( C(s) + O_2(g) \rightarrow CO_2(g) + 393.5 \, \text{kJ} \)[/tex]



Answer :

To determine which reaction shows that the formation of [tex]\( CO_2 \)[/tex] releases 393.5 kJ/mol, we need to recognize where energy should appear in the equation. When energy is released during a reaction, it is placed on the product side of the equation.

Let's analyze each given option:

Option A:
[tex]\[ C(s) + O_2(g) + 393.5 \text{ kJ} \rightarrow CO_2(g) \][/tex]
Here, energy is shown on the reactant side. This implies that energy is absorbed, which does not match our requirement of energy release.

Option B:
[tex]\[ C(s) + 2O(g) + 393.5 \text{ kJ} \rightarrow CO_2(g) \][/tex]
This option also places energy on the reactant side, similar to Option A, indicating energy absorption instead of release.

Option C:
[tex]\[ C(s) + O(g) \rightarrow CO_2(g) + 393.5 \text{ kJ} \][/tex]
This reaction includes energy on the product side, indicating that energy is released. However, it incorrectly shows [tex]\( O(g) \)[/tex] (oxygen atoms) instead of [tex]\( O_2(g) \)[/tex] (oxygen molecules). The correct substance should be [tex]\( O_2 \)[/tex] for proper stoichiometry.

Option D:
[tex]\[ C(s) + O_2(g) \rightarrow CO_2(g) + 393.5 \text{ kJ} \][/tex]
This reaction correctly places energy on the product side, indicating that energy is released. It also uses the correct form of oxygen [tex]\( O_2(g) \)[/tex].

Thus, the correct option that shows the formation of [tex]\( CO_2 \)[/tex] releases 393.5 kJ/mol is:

D. [tex]\( C(s) + O_2(g) \rightarrow CO_2(g) + 393.5 \text{ kJ} \)[/tex]