In August 2015, Educational Innovations was able to bring back goldenrod paper. For years, this paper had been discontinued, apparently because goldenrod paper was not able to be recycled. The fibers in the paper were saturated with golden colored dye.
Students often struggle with the difference between a solution that is buffered and one that is not.
Your students may find it interesting to compare the acid content of a low-acid apple juice or a low-acid orange juice to that in a regular juice of the same brand. These sample types could be added to an existing acid-base titration experiment, form the basis of a new experiment, or be used as project topics.
This is a favourite of the students. On the front cover, the pink colour in the test tube comes from cobalt(II) ions in water, Co(H2O)62+. The blue colour is the result of cobalt chloride complex ions (CoCl42–) in less dense acetone. This classic Le Châtelier’s Principle lab explores the reversible chemical reaction.
Penney Sconzo presented this nifty demonstration at the ChemEd 2015 Generations Symposium in Kennesaw State University, Kennesaw GA. This is an easy, colorful and safe microscale version of the Ammonia Fountain.
Part 1 of this article was published in Chem 13 News in November 2014. This second part presents three titration exercises of increasing sophistication, suitable for students with some titration experience. Citric acid and sodium hydroxide are used for all three presented titrations.
Citric acid is a user-friendly, inexpensive, water-soluble, crystalline solid carboxylic acid. In comparison to using hydro-chloric acid solutions, using solid citric acid and its solutions in water is safer and more convenient. For inexperienced students its titrations against strong base are easier to perform.