Oxidation and Reduction Activity 1.11 Heat a china dish containing about 1 g copper powder (Fig. 1.10). What do you observe? The surface of copper powder becomes coated with black copper(II) oxide. Why has this black substance formed? This is because oxygen is added to copper and copper oxide is formed. Figure 1.10

Double Displacement Reaction Activity Take about 3 mL of sodium sulphate solution in a test tube. In another test tube, take about 3 mL of barium chloride solution. Mix the two solutions (Fig. 1.9). What do you observe?