# Question #7eb16

Nov 30, 2015

Copper metal is oxidized to $C {u}^{2 +}$. The nitrogen of nitric acid is reduced from $V +$ to $I I +$.

#### Explanation:

Oxidation half equation:

$C {u}^{0} \rightarrow C {u}^{2 +} + 2 {e}^{-}$ $\left(i\right)$

$H \stackrel{+ V}{N} {O}_{3} + 3 {e}^{-} + 3 {H}^{+} \rightarrow \stackrel{+ I I}{N} O + 2 {H}_{2} O$ $\left(i i\right)$

Are both equation balanced with respect to mass and charge? I think they are (and they must be for a correct answer).

So now I cross multiply, $3 \times \left(i\right) + 2 \times \left(i i\right)$ (I do this to eliminate the electrons! which are included in the redox equations as conceptual particles):

$3 C u + 2 H N {O}_{3} + 6 {H}^{+} \rightarrow 3 C {u}^{2 +} + 2 N O + 4 {H}_{2} O$

Of course, since I am producing $C u {\left(N {O}_{3}\right)}_{2} \left(a q\right)$ I could write:

$3 C u \left(s\right) + 8 H N {O}_{3} \left(a q\right) \rightarrow 3 C u {\left(N {O}_{3}\right)}_{2} \left(a q\right) + 2 N O \left(g\right) + 4 {H}_{2} O \left(l\right)$

The last hurdle: is this equation balanced with respect to mass and charge? I leave it to you to decide. I might have made a mistake.