Students in Jessica Fitzgerald’s Chemistry II classes at Washington High School are diving back into chemistry with an engaging laboratory investigation designed to reinforce key concepts from their first year of study.

The focus of the lab was the compound copper (II) sulfate pentahydrate, a vivid blue crystalline substance that served as the basis for exploring the structure and behavior of hydrates. Students worked to determine both the percentage of water in the crystal and the mole ratio of water molecules to formula units of salt.

To complete the lab, students carefully measured the mass of the hydrate before and after heating, a process that removes the water and leaves behind the anhydrous form of the salt. The difference in mass provided data needed to calculate the percent composition of water in the original compound.

Through this hands-on experiment, students strengthened their understanding of chemical formulas, composition of compounds, and the Law of Definite Composition - a foundational principle stating that a chemical compound always contains exactly the same proportion of elements by mass.

The lab provided an opportunity for students to connect theoretical knowledge with practical investigation, helping to prepare them for more advanced chemical studies.

Photos from the WHS chemistry lab are below.