Oxalate Synthesis and Pyrolysis: A Colorful Introduction to Stoichiometry

Metal oxalate synthesis and pyrolysis provides an opportunity for students to (i) learn stoichiometry, (ii) experience the consequences of proper stoichiometric calculations and experimental techniques, and (iii) be introduced to the relevance of chemistry by highlighting oxalates in context, for example, usages and health effects. At our institution, general chemistry students synthesized the hydrated form of either iron(II), nickel(II), or manganese(II) oxalate. Synthesis was followed by oxalate pyrolysis and subsequent determination of the pyrolysis product’s identity, of three possible, using stoichiometric calculations and comparisons of theoretical and actual yields. Striking color changes that accompany these pyrolysis reactions were well received by students and served to highlight the chemical changes involved. Student actual yield values for both the iron and manganese pyrolysis products compared favorably with theoretical yield values and, in addition, 78% and 76% of students would have chosen ...