In an experiment, rusting steel wool soaked in vinegar showed a rising temperature on a thermometer. Which conclusion best follows from this observation?

In an experiment, rusting steel wool soaked in vinegar showed a rising temperature on a thermometer. Which conclusion best follows from this observation?

• A. Reaction released energy
• B. Reaction absorbed energy
• C. There was no chemical change
• D. Temperature reading was inaccurate

Answer: (A)

The main idea here is that a rise in temperature during a chemical process means energy is being released as heat to the surroundings. Rusting of steel wool in vinegar is a chemical change where iron reacts with oxygen to form iron oxide, and this reaction releases energy. The observed warming on the thermometer shows heat is being given off, which is what we expect from an exothermic process. If the reaction had absorbed energy, the temperature would drop or stay the same, not rise. Since rusting is indeed a chemical change, and the heat reading aligns with energy release, the conclusion that the reaction released energy best fits the observation.

The main idea here is that a rise in temperature during a chemical process means energy is being released as heat to the surroundings. Rusting of steel wool in vinegar is a chemical change where iron reacts with oxygen to form iron oxide, and this reaction releases energy. The observed warming on the thermometer shows heat is being given off, which is what we expect from an exothermic process. If the reaction had absorbed energy, the temperature would drop or stay the same, not rise. Since rusting is indeed a chemical change, and the heat reading aligns with energy release, the conclusion that the reaction released energy best fits the observation.