Endothermic reactions are reactions that proceed by the absorption of heat (energy) while exothermic reactions involve a release of energy.
a) Formation of frost on a car window in winter is an exothermic process as heat is liberated when liquid water freezes to form crystals
b) Formation of water condensate on a glass of ice water is an endothermic reaction since heat is absorbed by the cold water from the glass container thereby cooling it.
c) A decrease in the temperature as ammonium nitrate is added to water is an endothermic reaction
Answer:
The reactions in which heat is released are known as exothermic, and the reactions in which heat is absorbed are known as endothermic reactions. Â
a) Frosting comprises the transformation of water vapors present in the air into frost or ice by discharging energy as during the winters temperature is low. Thus a is an example of the exothermic process. Â
b) A large concentration of water vapors are present in the air and even the temperature is high on a humid summer afternoon. When the vapors encounter with ice water present in a glass, they get condensed to produce water droplets. The condensation discharges energy, hence b is an example of the exothermic process. Â
c) The dissolution of ammonium nitrate in water minimizes the temperature of the solution as it is utilizing energy from the surroundings. Thus, c is an example of the endothermic process. Â
