so I've been banging my head against this problem for a while now and I'm pretty sure I'm doing something wrong. this is the unbalanced reaction:
(may be important the mention: this is happening in acidic conditions.)
CuS(s) + HNO3
Cu(NO3)2 + H2O + NO(g) + S(s)
the first thing that I got stuck on was finding the oxidation states for the atoms in Cu(NO
3)
2. after doing some googling I found out that NO
3 should have a minus sign on it((NO
3)
-) which made some sense after drawing the lewis stracture for it.
after doing that I noticed that S and N changed their oxidation number(S was -2 and became 0, N was +5 and became +2).
However when writing the half reactions for oxidation and reduction, I got stuck. this was my process:
oxidation half reaction(unbalanced):
CuS(s)+ HNO
3 ![right arrow :rarrow:](https://www.chemicalforums.com/Smileys/classic/rarrow.png)
S(s)+ Cu((NO
3)
-)
2Cu and S quantities were already balanced, and the same goes for oxygen quantities. which only leaves balancing Hydrogen and nitrogen quantities like so:
CuS(s)+ 2HNO
3 ![right arrow :rarrow:](https://www.chemicalforums.com/Smileys/classic/rarrow.png)
S(s)+ Cu((NO
3)
-)
2 + 2H
+the weird thing is that after doing that the charges are balanced too, which makes no sense because that should mean there was no transfer of electrons and hence no oxidation.
as for reduction, I tried balancing this:
HNO
3 ![right arrow :rarrow:](https://www.chemicalforums.com/Smileys/classic/rarrow.png)
NO(g)
however, the weird thing is that H
2O is not present in either, and I have no idea how to include it.
summery of all of my questions:
1. Is the lack of a minus sign on (NO
3)
2 really a mistake or am I missing something? If it is intentional, how do I find the oxidation numbers for the atoms in Cu(NO
3)
2?
2. is my oxidation half-reaction correct? if not, what am I missing?
3. how do I involve H
2O in my half reactions?
I honestly tried to solve this for a long time and I'm not asking people to do it for me, I'm just really, really, bad at chemistry and I'm kinda stuck.