[StillLearning]

I've attached an image in a document of the problem i'm working on.  For the life of me I cannot figure out how to solve this.  I thought oxygen had an oxidation number of -2??  I'm so lost.  Would someone PLEASE help me with this.  Thanks in advance. 

[nj_bartel]

The oxidation state of pure uncharged elements (e.g. Cl₂, Li) = 0, always.

[StillLearning]

The oxidation state of pure uncharged elements (e.g. Cl₂, Li) = 0, always.

Would you mind helping me with the the problem attached in my original post?  Even with your above advice, i'm still not able to correctly solve the problem.  I'm stuck.

[nj_bartel]

What're the oxidation states of H₂, N₂, and O₂?  Hint - do they consist of just one element?  Hint₂ - what is the net charge on the compound?

[StillLearning]

What're the oxidation states of H₂, N₂, and O₂?  Hint - do they consist of just one element?  Hint₂ - what is the net charge on the compound?

Well, everything on the reactant side is a single element, so should it be 0?  If this is the case, then how do I determine the oxidation states of the elements on the product side? 

[nj_bartel]

You're right. Use your rules for heterogenous compounds now for the products.  Oxygen when combined with nitrogen has an oxidation state of...? -2. But your overall compound has a net charge of 0 and a molecular formula of N₂O.  So 2*(oxidation state of N) + -2 (the oxidation state we already have given by oxidation rules for oxygen being bonded to nitrogen) = 0 

solve for the oxidation state of N.

[StillLearning]

You're right. Use your rules for heterogenous compounds now for the products.  Oxygen when combined with nitrogen has an oxidation state of...? -2. But your overall compound has a net charge of 0 and a molecular formula of N₂O.  So 2*(oxidation state of N) + -2 (the oxidation state we already have given by oxidation rules for oxygen being bonded to nitrogen) = 0 

solve for the oxidation state of N.

Ok I think i'm starting to understand, but i've got a few more questions:

1.  So the oxidation state of N is +1 since there are 2 N atoms for every 1 O atom, right? 
2.  The coefficients always get ignored when looking at oxidation states, right?   
3.  Why is that in the compound 2NH₃ the anion comes first?  I thought the cation came first, or is that only in ionic compounds? 

[nj_bartel]

1) right
2) right
3) Not entirely sure on that, been a while since I've done this stuff.  If it isn't just ionic compounds, then ammonia (NH₃) might just be an exception because it could've been a compound that was discovered before the nomenclature was put in place.

[StillLearning]

1) right
2) right
3) Not entirely sure on that, been a while since I've done this stuff.  If it isn't just ionic compounds, then ammonia (NH₃) might just be an exception because it could've been a compound that was discovered before the nomenclature was put in place.

Hmm.  Ok.  I wont worry about that right now then.  I really appreciate your help.