When Plaster of Paris is mixed with water, it undergoes which of the following changes?

When Plaster of Paris (CaSO4·0.5H2O) is mixed with water, it undergoes an exothermic reaction, meaning it releases heat. The chemical formula for the reaction is: 2CaSO4·0.5H2O + 3H2O → 2CaSO4·2H2O. Mixing Plaster of Paris with water gives off heat because the reaction is exothermic. The water changes Plaster of Paris back into gypsum (CaSO4·2H2O), its original form before heating. As gypsum forms, its crystals lock together, creating a hard, solid structure. This quick-setting property makes gypsum useful in construction, sculpture, and medical casts.