The application of Hess's Law frequently presents students with conceptual problems. This series of experiments confirms Hess's Law and offers a robust understanding of this principle. This can be done as a demo completed by the teacher or as a lab with groups of students.
If rhubarb stem is placed in a solution of permanganate, the purple permanganate ion is reduced to the colorless Mn2+ ion. It is thought that the oxalic acid present in rhubarb causes this reduction. The investigations presented in this post provide evidence that this may not be the whole story...
A description of a quick and easy lesson that is sure to add some spark into your next lesson on stoichiometry.