The steel wool and vinegar experiment produced a temperature increase, indicating the reaction is which type?

• A. Exothermic
• B. Endothermic
• C. Photochemical
• D. No reaction

Answer: (A)

This question tests how to tell if a reaction releases or absorbs heat. When a reaction is exothermic, energy is released as heat to the surroundings, so the temperature rises. In the steel wool and vinegar experiment, the visible warming shows heat being released, indicating an exothermic process. Endothermic reactions would cool the surroundings because they absorb heat, photochemical reactions involve light rather than heat change, and saying no reaction would mean no measurable temperature change. The rusting of iron in the presence of vinegar releases energy as bonds form, which fits an exothermic reaction.