This activity allows students to visualize how to obtain different stoichiometries with various techniques in a single experiment. The involvement of three phases adds to the student's interest. Instructional materials are provided to facilitate the experimental procedures, interpretation of results, and error analysis. The reaction of Li from a Li battery with water inside a syringe allows measurement of the gas evolved, the metal consumed, and the hydroxide produced. Li batteries can be obtained for less than US $1.00. This report describes the development of a 2 h activity that has been tested in whole or in part in various teacher workshops in Mexico, Panama, El Salvador, and Thailand, and it has been implemented and assessed in a general chemistry laboratory.