On-Level Chemistry Students Explore Mixture Separation

Dr. Kim Rehwoldt’s Upper School On-level Chemistry students recently conducted a “Separation of a Mixture” lab, putting their scientific knowledge and laboratory skills to the test. The lab gave students the opportunity to explore both physical and chemical separation techniques while working with a heterogeneous mixture of salt, sand, and limestone.

The experiment began with students dissolving the salt in water, carefully separating it from the sand and limestone. They then evaporated the water over a Bunsen burner, leaving the pure salt behind. This portion of the lab highlighted physical separation methods and demonstrated the practical applications of solubility and evaporation.

Next, students turned their attention to the limestone. By adding hydrochloric acid, they observed a chemical reaction that produced carbon dioxide gas and soluble calcium chloride. This reaction allowed students to separate the calcium chloride from the sand, which remained unaffected by the acid. Through this process, students gained hands-on experience with chemical reactions, solubility, and gas production.

The lab provided an exciting, hands-on learning experience that brought chemistry concepts to life. Students not only mastered essential techniques but also experienced the thrill of discovery firsthand—watching bubbling reactions, separating mixtures, and transforming materials before their eyes. The engaging approach left students energized, curious, and eager to explore the next challenge in the world of chemistry.