The experimental procedure and student results for the analysis of several mineral water brands in a multi-section general chemistry course are presented and discussed. Four commercial mineral water brands were analyzed for total dissolved solids (TDS), total water hardness expressed as ppm of calcium carbonate, and pH. These are important and regularly monitored water quality parameters. Gravimetry, ethylenediaminetetraacetic acid (EDTA) complexometric titration, and pH measurements were applied to real-world samples that are familiar to students. In addition to its daily life relevance, this laboratory experiment provided a milieu for general chemistry students to evaluate the precision of multiple data sets and to establish a connection between their laboratory experience and topics covered in lecture such as acid-base, buffer, complex formation, and stoichiometry and concentration unit conversion. Overall, the students’ results for all parameters had good precision and were in reasonable agreement with the published values.
Bazzi et al. (Wed,) studied this question.