$$2Ag_2O_{(s)} \rightarrow 4Ag_{(s)} +O_{2(g)}$$

In this reaction, silver oxide decomposes into silver metal and oxygen gas. Silver undergoes a reduction from an oxidation state of +1 in Ag2O to 0 in Ag, while oxygen undergoes an oxidation from an oxidation state of -2 in Ag2O to 0 in O2.

2. Reaction of copper and nitric acid:

$$Cu_{(s)} + 4HNO_{3(aq)} \rightarrow Cu(NO_3)_{2(aq)} + 2NO_{2(g)}+ 2H_2O_{(l)}$$

In this reaction, copper metal reacts with nitric acid to form copper nitrate, nitrogen dioxide gas, and water. Copper undergoes an oxidation from an oxidation state of 0 in Cu to +2 in Cu(NO3)2, while nitrogen undergoes a reduction from an oxidation state of +5 in HNO3 to +4 in NO2.