Relating chemical formulas to actual substances can often be a confusing and difficult challenge for students. In this Applied Science Concepts Kit, abstract theories are made concrete, as students learn to predict the formula of a compound based on the compound's reaction to different solutions. Students use a chemical analysis method to determine percent composition and molecular weight of a molecular substance. For ionic substances, students will determine the relative number of each of the ions in substance's composition. This lab is complete for 50 students. The methods used in this kit for determining chemical formulas are also used in the Families of Elements Experiment Kit, LAB-110R.