Students can build their own Hoffman apparatus. An animation of the electrolysis on a particulate level is available to show students before, during or after students perform the electrolysis.
I have used several different versions of the Silver Mirror or Tollen's Test lab. I am sharing the method that has proven to be the most reliable for me. The solutions should be made fresh, the directions must be followed closely and timing is very important. I like the fact that relatively small amounts of the chemicals are required, but as always you must be vigilant with safety precautions.
My IB seniors are just wrapping up our unit on electrochemistry and redox. This has always been a challenging topic within the IB curriculum. Admittedly, electrochemistry has not ever been my strong suit either, so this year I aimed to strengthen the unit with two additional demonstrations.
The chemistry of silver and the process in which silver becomes tarnished is explored. Take a new look at an old JCE Classroom Activity.
During our recent chemistry summer camp, we used some electrochemistry activities. We had some logistical issues, but they were an overal success!
In this Activity, students construct a simple battery from aluminum foil, saltwater, and activated charcoal. The battery can power a small motor or light. This Activity demonstrates oxidation and reduction reactions, which are integral parts of battery chemistry.
In this Activity, students remove tarnish from silver using the reaction of tarnish with aluminum. If only untarnished silver items are available, students first tarnish them using items that contain sulfur. This Activity could be used with topics such as chemical changes, metals, electrochemistry, and redox reactions. The Activity could introduce a discussion of silver and its reactions.
In this Activity, students investigate static electricity. They observe that charged objects attract a narrow stream of water, and find that charged combs and glass rods have opposite charges. This Activity could be used to introduce the notion of positive and negative electric charge. It is appropriate when studying atomic theory, and when introducing electrochemistry.
In this Activity, students determine the concentration (percent volume) of oxygen in air. They place small quantities of fine steel wool into a test tube that is then inverted in a beaker of water. Oxygen in the trapped air reacts with the iron to form rust. The Activity ties in well with atmospheric chemistry.
Looking for an easy, hands-on experiment to use in your classroom at the beginning of the school year? In the June, 2013 issue of the Journal of Chemical Education, Isao Ikemoto and Kouichi Saitou describe a simple experiment to demonstrate the electrolytic dissolution of copper ions from a copper electrode. This experiment can be conducted using only items that are easily obtained around the home or in grocery stores.
