Cu + O2 -----> 2CuO
[tex]( Cu^{0} -2 e^{-} -----\ \textgreater \ Cu^{+2}) *2 / oxidation
O_{2} +4 e^{-} ------\ \textgreater \ 2O^{-2} / reduction
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2Cu^{0} + O_{2} ^{0} -----\ \textgreater \ 2 Cu^{+2} + 2 O^{-2} [/tex]
