Not all reactions give off heat like this. In fact, some actually take in or absorb energy from their surroundings, and the reacting substances feel cold. They’re called endothermic reactions.

Commercial heat packs (containing iron and water, or supersaturated sodium acetate) and cold packs (various ammonium salts) can be used to show exo- and endothermicity. Heat packs that contain iron ...

In this reaction, the temperature goes down, so it is endothermic. In an endothermic reaction, more energy goes into breaking the bonds of the reactants than is released when the bonds in the products ...

Incredibly, the reaction between iron and moist air that produces rust is a very exothermic process and generates lots of heat. Unfortunately, this particular reaction takes place so slowly that ...

Students investigate reactions which produce a gas, form a precipitate, and cause a color change. Students also explore endothermic and exothermic reactions and do an engineering activity to design a ...