how to find oxidation in reactions?

Question

anonymous · Answer

Do you want the oxidation number or reaction?

anonymous · Answer

for example: Zn + H2SO4 → ZnSO4 + H2 . How do you know which element is oxidized or how do you come to this answer. I wasn't able to assists a few classes and I got lost in that area.

anonymous · Answer

This is probably a redox reaction. Here Zn is oxidized to ZnSO4 and H2SO4 is reduced to H2

anonymous · Answer

but how do you come to the conclusion that Zn is oxidized?

anonymous · Answer

have a look at this http://answers.yahoo.com/question/index?qid=20101007205620AA8DRI9

anonymous · Answer

but why the oxidation changes on Zn 0 to +2

jfraser · Answer

We figure out oxidation states by looking at the charges of each piece. Since Zn as a reactant is separate, it has an oxidation of zero; it is neutral. As a product, Zn is paired with $SO_4$, so it must have an oxidation of +2. The Zn must lose 2 electrons to go from a 0 state to a +2 state, so it is oxidized:$$Zn^0 \rightarrow Zn^{+2} + 2e^{-1}$$the sulfate isn't actually important at all