Question

the $\delta h_{\text{rxn}}$ of formation of carbon dioxide is negative. which statement is true?
the amount of carbon dioxide is more than the amount of reactants.
the reaction is exothermic.
the amount of carbon dioxide is less than the amount of reactants.
the reaction is endothermic.

Explanation:

To determine the correct statement, we analyze the meaning of a negative $\Delta H_{\text{rxn}}$ (enthalpy change of reaction) for the formation of carbon dioxide. A negative $\Delta H$ indicates that the reaction releases heat, which is the definition of an exothermic reaction. The amount of products (carbon dioxide) versus reactants is related to stoichiometry, not directly to the sign of $\Delta H$. An endothermic reaction has a positive $\Delta H$, so that is incorrect. The statements about the amount of carbon dioxide relative to reactants are not determined by the enthalpy sign. Thus, the correct statement is "The reaction is exothermic."

Answer:

The reaction is exothermic. (The option with the text "The reaction is exothermic.")