When calcium oxide (CaO) is added to water, it reacts exothermically to form calcium hydroxide (Ca(OH)₂). This means that heat is released during the reaction, resulting in a rise in temperature of the solution.
On the other hand, when barium hydroxide (Ba(OH)₂) is mixed with ammonium chloride (NH₄Cl), the reaction is endothermic. In this case, the process absorbs heat from the surroundings, causing a decrease in temperature. The heat absorbed is used to break the bonds in the reactants, resulting in a cooling effect.
In summary:
– CaO + Water: Exothermic reaction → temperature rises.
– Ba(OH)₂ + NH₄Cl: Endothermic reaction → temperature falls.
