Caption:
Endothermic reaction, image 2 in a series of 2. Dissolution of ammonium nitrate (NH4NO3) in water is an endothermic reaction, i.e. the energy is absorbed from the surroundings: NH4NO3 -> (NH4)+ + (NO3)-. Here 30 g of ammonium nitrate is added to a beaker with 120 mL of water, initially at 25 C (Photo 1). After ammonium nitrate is dissolved, the temperature drops to 12.7 C (Photo 2).