Elements and the periodic table > displacement

In this experiment copper(II) oxide and zinc metal are reacted together. The reaction is exothermic and the products can be clearly identified. The experiment illustrates the difference in reactivity between zinc and copper and hence the idea of competition reactions.

Copper(II) oxide reacts with magnesium

Oxygen is bubbled through solutions of potassium sulfide, chloride, bromide and iodide to establish which non-metallic elements are displaced from their compounds by oxygen. Then chlorine water is added to the same solutions to establish which elements are displaced by chlorine. Finally the class can decide to which solutions bromine water should be added to complete this displacement series for

A ‘copper’ coin is dipped into a solution of sodium zincate in contact with zinc metal. The coin is plated with zinc and appears silver in colour. The plated coin is held in a Bunsen flame for a few seconds and the zinc and copper form an alloy of brass. The coin now appears gold.

This lesson is designed to exemplify an argumentation approach to practical work, using a ‘predict, observe, explain’ framework.