The demonstration illustrates the dissolving process and the energy changes that accompany dissolving. The dissolving of ammonium chloride is endothermic while the dissolving of calcium chloride is exothermic. Done in Ziplock® bags, the changes in temperature can be sensed by students by passing the bags around the class for inspection. The demonstration can also be used to discuss the changes in energy, entropy, and free energy.
Key Words:
endothermic, exothermic, dissolving, spontaneous, enthalpy, entropy, free energy, heat of solution