Identify the substances that are oxidised and that are reduced in the following equation.

i) 4Na(s) + O2(g) → 2Na2O(s)

ii) CuO(s) + H2(g) → Cu(s) + H2O(l)

The Sodium (Na) in the first equation is getting oxidized with the addition of Oxygen (O2), and the Copper (Cu) in the second equation is reduced due to the addition of Hydrogen (H2).