How to Balance redox reaction with half reaction? With the example of the unbalanced one: Al+Fe2O3=Fe+Al2O3

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Welcome to balancing redox reactions using the half-reaction method. This systematic approach helps us balance complex equations by separating oxidation and reduction processes. Let's examine the reaction between aluminum and iron oxide to form iron and aluminum oxide. The first step is to assign oxidation states to identify which elements undergo oxidation and reduction. Aluminum goes from zero to plus three, losing electrons in oxidation. Iron goes from plus three to zero, gaining electrons in reduction. Oxygen remains at minus two throughout the reaction. Step two involves writing separate half-reactions for oxidation and reduction. The oxidation half-reaction shows aluminum forming aluminum oxide, while the reduction half-reaction shows iron oxide forming iron. Each half-reaction will be balanced separately for atoms and electrons before combining them. Step three involves balancing each half-reaction for atoms and electrons. In the oxidation half-reaction, we need two aluminum atoms to form one aluminum oxide molecule, and we add six electrons to balance the charge. In the reduction half-reaction, we balance iron atoms with a coefficient of two and add six electrons. Notice that both half-reactions now have six electrons, which will cancel when combined. In the final step, we combine the balanced half-reactions and cancel the six electrons that appear on both sides. This gives us the balanced equation: two aluminum plus iron two oxide yields two iron plus aluminum two oxide. We can verify this is correct by checking that atoms and charge are balanced on both sides. The half-reaction method provides a systematic approach to balance even complex redox equations.