[Atome]

Hello everyone,

For the following practice problem, I arrived at the same answer as the one in my textbook. However, I am studying for AP Chemistry by myself and since the textbook does not explain the answer, could someone please verify my solution?

Thank you.

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1. The compound Fe₃O₄ contains both Fe²⁺ and Fe³⁺ ions. What is the average oxidation number of iron in this oxide?

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Since oxygen's oxidation state is -2, the "equation" representing oxidation states would be:

Oxidation State of Fe₃ + (-2 x 4) = 0

Therefore:

Oxidation State of Fe₃ = 8

Oxidation State of Fe  = 8/3

= Avg. Oxidation State because the ionic charge is irrelevant.

[Yggdrasil]

Your answer looks correct.  Now for fun, can you figure out how many iron (III) and iron (II) ions are in Fe₃O₄?

[Atome]

Thanks for your response, yggdrasil. I missed your question.

Would there be three ferrous and ferric ions in Fe₃O₄?

[Borek]

Fe₃O₄ can be treated as mixed oxide Fe₂O₃^.FeO.