Over time, students become familiar with the properties of elements and their characteristic reactions that form compounds and molecules. In this three-part demonstration, show the other side of that coin by using characteristic reactions to produce elements from compounds.
- Tin, Sn—What happens in an electrolytic cell if one of the ions in the electrolyte may be both oxidized and reduced? Electrolysis of tin(II) chloride provides a stunning example. Grow a beautiful “tin-man” crystal tree by running an electric current through a solution of tin(II) chloride. Students will enjoy this “electric” oxidation–reduction demonstration as elemental tin is produced. What happens if the current is reversed?
- Silver, Ag—A copper wire coil is suspended in a silver nitrate solution. The coil is coated with shiny elemental silver “needles,” and the solution turns blue as silver ions are replaced by copper ions.
- Carbon, C—Your students will be amazed as they watch a yellow solid–liquid mixture turn brown, then black, expand out of the top of the beaker and solidify. The beaker becomes extremely hot, and the odor of burnt sugar becomes noticeable. The solid black product is pure elemental carbon!
Includes detailed instructions, a reproducible student worksheet, and Teacher Notes with tips and answers to all questions.Concepts:
Electrolysis, cathode, anode, oxidation–reduction, single replacement reaction, dehydration reaction, exothermic reactions. Time Required:
30 minutes Chemicals Provided:
Copper wire, silver nitrate solution, sodium carbonate, sucrose, sulfuric acid, tin(II) chloride solution.