CH↓4 + 2 O↓2 CO2 + 2+ ↓20
-
CH4 + 2 O2 → CO2 + 2 H2O
First, we must assign oxidation numbers to each and every atom on each side of the above equation:
Left side:
C = -4
H = +1
O = 0
Right side:
C = +4
H = +1
O = -2
Comparing oxidation numbers on each side, we see that both carbon and oxygen changed oxidation numbers. The following half-reactions answer your question:
O + 2 e^- → O^2-
Each oxygen atom gains two electrons and becomes reduced.
C^4- – 8 e^- → C^4+
Each carbon atom loses 8 electrons and becomes oxidized.
First, we must assign oxidation numbers to each and every atom on each side of the above equation:
Left side:
C = -4
H = +1
O = 0
Right side:
C = +4
H = +1
O = -2
Comparing oxidation numbers on each side, we see that both carbon and oxygen changed oxidation numbers. The following half-reactions answer your question:
O + 2 e^- → O^2-
Each oxygen atom gains two electrons and becomes reduced.
C^4- – 8 e^- → C^4+
Each carbon atom loses 8 electrons and becomes oxidized.