Redox Equation and Half equation

2Mg+ O2 →   2MgO

0           0             +2 -2

The diagram above shows that Mg to Mg 2+ is oxidation (reducing agent)

O2 to O2- reduction occurs (oxidizing agent)

Half equation

Some reactions maybe written in 2 halves (the oxidation half and the reduction half). The 2 parts are called the half equations.

2Mg+ O2 →  2MgO

Oxidation                                                                       reduction

2Mg -4e-   →     2Mg2+                                                                                          O2 +4e-   →       2O2-

Electrons are lost                                                                                          electrons are gained

Redox Reaction

Zn + CuSO4 →  ZnSO4 +Cu

0      +2              +2                0

Half equations

Oxidation: Zn -2e-      →      Zn 2+     reducing agent

Reduction: Cu 2+ +2e-    →     Cu   oxidizing agent

Try:

Zn + H2SO4 →    ZnSO4 +H2

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