Examples of Endothermic Reactions

Endothermic reactions absorb heat energy from the surroundings. So that the temperature of the surroundings decreases. In endothermic reaction, the products formed are at a higher energy level than that of the reactants; hence energy is absorbed by the reactants from the surroundings.

Photosynthesis is an endothermic reaction.

 

In endothermic reactions, more energy is required to break bonds than is required to make bonds. Energy is absorbed and the surroundings get cooler. Sometimes you may see sportsman and women putting cold packs on injured ankles, knees or other parts of their bodies. One types of cold packs uses an endothermic reaction to work. The cold packs contains water and ammonium nitrate. As the ammonium nitrate dissolves in water an endothermic reaction takes place and the ice pack becomes very cold.

Some of the examples of endothermic reaction are given below:

1. Decomposition of compounds such as calcium carbonate, copper (II) carbonate, sodium nitrate etc.
2. Food being cooked.
3. Photosynthesis where green plants absorb light energy to make starch.
4. Dissolution of ionic salts like ammonium chloride, ammonium nitrate and sodium carbonate crystals in water.
5. Taking a photograph with a film, light energy is absorbed to decompose the silver bromide on the film to silver and bromine.

Endothermic reactions are less common than exothermic reaction, but there are a number which are quite familiar. For example, when certain salts such as potassium chloride and ammonium nitrate dissolve in water they take in heat from the surroundings and the temperature of the solution drops.