Question

which statement is true if the $\delta h_{\text{rxn}}$ of a reaction is positive?
the reaction is endothermic.
there is more reactant than product.
there is more product than reactant.
the reaction is exothermic.

Explanation:

To determine the false statement when $\Delta H_{\text{rxn}}$ is positive, we analyze each option:

• Endothermic reaction: A positive $\Delta H_{\text{rxn}}$ means the reaction absorbs heat (endothermic), so this is true.
• Reaction type (exothermic): Exothermic reactions release heat, so $\Delta H_{\text{rxn}}$ is negative. A positive $\Delta H_{\text{rxn}}$ cannot be exothermic, so this statement is false.
• Reactant/product ratio: $\Delta H_{\text{rxn}}$ (enthalpy change) does not directly determine the amount of reactants or products (that relates to equilibrium/stoichiometry, not enthalpy). So claims about "more reactant" or "more product" based on $\Delta H_{\text{rxn}}$ are incorrect, but the "exothermic" statement is definitively false (unlike the reactant/product claims, which are just irrelevant to $\Delta H$).

Answer:

The reaction is exothermic.