Letter from Melbourne

摘要

I was browsing through the Journal of Chemical Education when I came across an article entitled 'The dissolution of tin in solutions of iodine', in which the authors describe an exercise in kinetics. It's done with 15 mm discs of tin, 2 mm thick (and thus weighing about 2 grams), that are suspended by a thread from an analytical balance so that the metal is immersed in a solution of iodine in benzene. The weight of the disc decreases linearly with time, a typical result showing loss of about 1.8% in 15 minutes.