Chapter 20 - Oxidation-Reduction Reactions - 20 Assessment - Page 720: 34

a. 2Ba(s) + O2(g) = 2 BaO(s) b. CuO + H2 = Cu + H20 c. C2H4(g) + 3O2(g) → 2H2O(l) + 2CO2(g) d. 3CaO(s) + 2Al(s) → Al2O3(s) + 3Ca(s)

Barium has lost 2 electrons Oxygen has gained 2 electrons b. CuO + H2  Cu + H20  Cu was oxidized.  H2 was reduced C was oxidized.  O2 was reduced D.  Calcium is reduced  Aluminum is oxidized