Science, Tech, Math › Science How to Create an Exothermic Chemical Reaction Share Flipboard Email Print JMacPherson Science Chemistry Projects & Experiments Basics Chemical Laws Molecules Periodic Table Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated July 16, 2018 Exothermic chemical reactions produce heat. In this reaction, vinegar is used to remove the protective coating from steel wool, allowing it to rust. When the iron combines with oxygen, heat is released. This takes about 15 minutes. What You Need ThermometerJar with lidSteel woolVinegar Instructions Place the thermometer in the jar and close the lid. Allow about 5 minutes for the thermometer to record the temperature, then open the lid and read the thermometer.Remove the thermometer from the jar (if you didn't already in Step 1).Soak a piece of steel wool in vinegar for 1 minute.Squeeze the excess vinegar out of the steel wool.Wrap the wool around the thermometer and place the wool/thermometer in the jar, sealing the lid.Allow 5 minutes, then read the temperature and compare it with the first reading. Results Not only does the vinegar remove the protective coating on the steel wool, but once the coating is off, its acidity aids in oxidation (rust) of the iron in the steel.The thermal energy given off during this chemical reaction causes the mercury in the thermometer to expand and rise up the column of the thermometer tube.In the rusting of iron, four atoms of solid iron react with three molecules of oxygen gas to form two molecules of solid rust (iron oxide).