Answer:
2. Balanced
3. Not Balanced
Explanation:
2. 2CaO -> 2 Ca & 2 O
-yield-
2Ca + O2 -> 2 Ca & 2 O
In the chart: [left] Ca: 2; O: 2 [right] Ca: 2; O: 2
3. Al2O3 -> 2 Al & 3 O
-yield-
Al + O2 -> 1 Al & 2 O
In the chart: [left] Al: 2; O: 3 [right] Al: 1; O: 2